welcome to this course is going to be a ten lecture mock spread over about four weeks

ah this mock will have ah these lectures and there will be some assignments that come ah

ones a week or so in addition there will be some ah numerical problems or thought based

problems that we will discuss in class and probably assign some problems ah you would

have time to do it and we will check up with solutions in the next class the organization

of ah this course ah probably you may not find in text books in a complete way ah however

two books may be useful two you can consider them as ah reference books the first one is

shuler and kargi ah i will give you the details in one of the files that you can download

ah from the course site ah thats a nice book in addition there is an older book ah very

old ah eighty six it is by bailey and ollis thats also a good book but it is somewhat

dated in um going forward ah this would be an introduction the first ah lecture is going

to be an introductiots start with cancer we all know that cancer is an important disease

now a days it is been an important disease for a very long time decades may be and still

it is not been completely conquered there is lot of progress that has been made in treating

cancer in ah diagnosing cancer but we have still not completely overcome it and it is

still one of the important diseases of today what is cancer very simplistically speaking

it is the uncontrolled growth of cells we all know this the cell has lost its ability

to die when its job is done and when that happens cancer happens and thats one of the

ways cancer happens for example ah this is a nice example to give you if you look at

a hand and if you look at how this hands started out ah in a fetus it would have been a complete

completely filled end of a mass then the cells here started dying away and that is what gave

rise to the digits therefore in other words the cells here actually committed suicide

and that is what gave us these digits which are functioning

so cell death is an necessary part of the developmental process the regenevation regeneration

process and so on in the body and of that goes haywire and the cells continues to live

then it is also an cancer why is cancer dangerous its just cell that is there which is lots

ah cells cells they have lost their ability to die so why should it bother us it bothers

us because a lot of such cells in the body can threaten life itself as they interfere

with the crucial functions of organs and tissues for example let us take the lung if the lung

cells become cancerous they start growing uncontrolled and they interfere with the gas

exchange that happens in the lungs which is whittle to keep ah up life and so on so for

you can talk of ah different organs in the body may be liver may be kidney and if there

are ah cells that continue to grow and refuse to die then it interferes with the normal

function of those organs and that ultimately leads to death in a simplistic sense there

are other ah complications also there but this is one of the things that leads to death

therefore again ah straight forward thinking fashion to treat cancer the cancerous cells

need to be killed how do you kill it you use drugs cancer drugs and such a treatment is

called chemotherapy you could use radiation such a treatment it is called radiotherapy

and so on to ah kill cancer cells our these therapies you know you taken drugs to kill

the cancer cancer cells it could also kill the other normal cells in the body and that

is what leads to the undesirable side effects such as the hair falling out and various other

side effects of chemotherapy and radiotherapy which is not desirable so it becomes ah helpful

to target the killing agents the drugs that kill the cancer cells directly to the cancerous

cells so that the effect on the normal cells is minimal to target these drugs to the cancer

cells now a days something called monoclonal antibodies or m a bs are used at least for

some cancers some cancers it is been very effective these um ideas started decades probably

at decade and a half ago or more ago and then they have come to flowtion ah probably a few

years ago now they are effective again some types of cancer

monoclonal antibodies are made by cells called hybridomas hybridoma as the name suggest hybrid

oma it is a fusion or a mixture of a cell that can produce one type of antibody and

therefore you call them monoclonal antibodies and an other type which does not die ah which

this is a cancerous cell so if you use them together you have a cell that produces one

type of antibodies monoclonal antibodies and can live forever which becomes useful outside

the body when you trying to produce these monoclonal antibodies that are used to target

the drugs to cancerous cells the ah hybridomas themselves were developed in the mid seventies

by kohler and milstein and its potential was ah realized quite soon as soon as it was developed

and ah monoclonal antibodies became a rates even in the early eighties some of my work

doctoral work was related to monoclonal antibody production in a bioreactor these are some

of the monoclonal antibodies that have been used now a days to treat cancer rituximab

trastuzumab bevacizumab cetuximab panitumumab ipilimumab and so on and so forth

if you see here it ends in m a b which stands for monoclonal antibody and each one is effective

against certain kinds of cancers for more information you could look at this website

i am going to list all these websites in a separate file and ah put it up on your course

page so that is it is easier for you to reach these websites will have some of these websites

throughout the course more so in the introductory modules ah so that ah um you can go and read

about them get in death of those aspects because we will cover whatever is necessary for us

in this particular course but they by themselves could be very interesting to some of you so

you could go and read about them and dig further about them based on your interest the file

is going to be something like this the u r l that i gave you just now is the first u

r l ah cancer treatment here this one says websites videos recommended that could be

some videos also along with this this is a website cancer treatment and this was the

address that was given here you could download this file and click on the appropriate link

i guess you need to use a control or something like that before you click here and then you

would access the website and see through it

this is a nice website for cancer treatment ah i will highlight as we go through the lecture

the various websites there is an other website that is given there i think which is given

number two on that list we just saw that list and lets now come back from cancer to our

bioreactors course now what is the relevance here the relevant question here is that how

are monoclonal antibodies or m a bs made in large quantities that are needed for therapy

the amounts would be very small if you grow hybridomas in small vessels as they were done

initially but the demand for m a bs is huge now a days

so how do you produce the large quantities of m a b that are needed for therapy the answer

is through something called a bioprocess ok let me live it there for the time being and

we will keep visiting this bioprocess and then i will tell you what that is lets guess

the alternative liquid fuels where in great demand or ah where kind of hot a few years

ago they are still ah of great interest they are ah fuels that would replace the petroleum

or diesel that comes from crude oil the justification was the need was the crude oil sources are

running out and therefore we need alternative liquid fuels it is rather difficult to replace

liquid fuels its rather difficult to ah imagine um how a plane would fly without a liquid

fuel at least for some time to come or to there are other alternatives available now

on an experimental basis ah still probably we need a lot of liquid fuels two examples

of liquid fuel are bio ethanol and bio diesel ethanol you know c two h five o h that is

found in a lot of theses intoxicating drinks also but in a puro form if it is mixed with

some amount of ah petrol and ah or gas as it is called in some countries and used in

cars then thats a very good fuel but how do you get bio ethanol that is the source of

bio ethanol is con or other ah plant sources that ultimately give us the ethanol how do

you go from con for example two ethanol that is a because con contains various other things

it does not contain ethanol so how do you contain whatever con has to the ethanol that

is useful has a bio fuel thats a long process its also through a bio process

similarly bio diesel bio diesel is being used in a country from plant sources to run railways

and things like that to a reasonable extent you could also use something called micro

algae to produce bio diesel because micro algae accumulates what is called bio oil and

that bio oil can be convert its somewhat equivalent of the crude oil not exactly somewhat equivalent

of the crude oil and that bio oil can be processed to produce bio diesel so if you are using

micro algae which is a higher generation bio fuel compared to the plant based bio fuel

bio diesel then you need to use a bio process that converts um the raw materials sometimes

it could just be the carbon dioxide in the air and in the presence of sunlight and so

on through photosynthesis to yield bio oil which can then be convert it to bio diesel

so this process also is a bio process so bio processes are required for production of certain

alternative liquid fuels such as bio ethanol and bio diesel i would like you to look at

ah this animation which gives you details about ethanol making it gives you ah in a

nice way how ethanol is made from ah a con or some other source here similarly ya this

is ethanol from con this is ethanol making in general and animation and then this is

algae to fuels

ah if you are ah enable to read it here or use it directly from this presentation please

look at i think it is four five ethanol animation is three ethanol from con is four and algae

to fuels is number five on this list you could go through these sites which are commonly

available videos and ah get some information in a nice way in a non boring way and ah that

might be useful lets get back to our presentation here so the production of bio ethanol and

bio diesel are also done through bio processes another stretch here you all heard of insulin

what is insulin it is a drug that is used to treat diabetes a widely used drug that

is used to treat diabetes if you look at what kind of a molecule it is it is something called

a protein i i hope you have some background in ah bio molecules and so on so it is one

kind of a bio molecule um amino acid and a polymer of amino acid is a protein so insulin

is really small protein it was discovered in the nineteen twenties a long time ago and

soon people found ah that you could use it to treat diabetes and the initial source of

insulin was pig pancreas ok probably a few years after this till about nineteen eighties

they were obtained from the pancreas of pigs the numbers are quite staggering you need

about eight hundred two thousand k g of pancreas to produce hundred grams of insulin which

ah is a very very small amount compared to the world wide demand for insulin to treat

diabetes its a very very small amount not just that pancreas only one of these organs

of the body so you can imagine what needed to be done to get insulin when no other method

was known

however when a bioprocess for insulin became available because of the ease of getting insulin

this immediately reduced the cost of insulin by twenty four fold and this is also a bioprocess

this is the next video there ah on insulin that is given in your list you can go and

look at this to get some idea of the relevance of insulin the production of insulin through

a bioprocess and so on ok now lets come closer to home how do you think curd or yoghurt is

made you take milk you heat it to certain warmth in a vessel and then you add some old

curd to this slightly warmish milk and set is set it aside there are also curd makers

that maintain this vessel at thirty seven degree c just by some electrical means and

when this is done in a curd maker curd forms in about two hours or so if you live it over

night at home assuming that the outside temperature is reasonable then curd forms over night very

nicely

what is happening here ok let me introduce some terms that will be using frequently in

this course the milk that you initially take we can call it the medium right the nutrients

a nutrient broth using the nutrients in the nutrient broth the inoculum the small amount

of curd that you add it that contains organisms the organisms utilize the nutrients in the

medium and grow when these organisms grow these particular type of organisms ah they

are called lactobacillus when they grow they produce something called lactic acid you all

know what an acid does it reduces the p h and because of the controlled production of

acid in an appropriate fashion the p h gets reduced in an appropriate way along with other

things happening in the milk and a protein in the milk called casein curdles and thats

how we get curd appropriately ah you know even the the taste is made appropriate in

the process because of the way in which it gets done and then you could eat curd

very simplistically speaking curd making is also a bio process ok you have a vessel you

have a medium and you ah which contains a medium and then you add ah curd to it so you

have added inoculum to it the cells in the inoculum multiply and make more cells make

a product lactic acid and the lactic acid does something to the milk to give you curd

so this simplistics simplistically speaking is actually a bio process if a curd making

is also a bioprocess so let us look at what actually a bioprocess is this is an overview

of the bioprocess the bioprocess has two major aspects one is the bioreactor aspect this

is called also called the abstream aspect and a huge aspect here called the downstream

processing aspect the bioreactor is represented here by this we will see this in detail later

the raw material for example it could be the milk in the in the case of curd this enters

the bioreactor the bioreactor contains the micro organism of interest along with the

nutrient as we saw in the case of curd making the nutrients that are getting converted to

curd as well as the lactobacillus that converts it into curd or it could even have just an

enzyme which does some enzymatic conversion so after this process is done there are various

ways in which the process is done we will look at the details later

after the process is done what comes out of the bioreactor what is harvested from the

bioreactor contains the product of interest the micro organism and probably other material

we all are interested only in the product therefore we need to separate and purify the

product from these other things that are there and that is what is done through what is called

downstream processing there could be very many steps in downstream processing in fact

the number of steps in downstream processing could constitute about ninety five percent

of the steps in a bioprocess so large number of steps in downstream processing and finally

at the end of it all we have the final purified product so this is a bioprocess this course

will focus on the abstream side or the bioreactor side downstream processing of course is very

important but the focus in this particular course because we need to focus on something

to get something useful out of what ever we are doing and we are going to focus on the

bioreactor aspect or the abstream aspect typically the bioreactor aspect and thats why this mock

is called a bioreactors

as was clear from the previous slide the bioreactor is at the heart of a bioprocess that is necessary

for a bioprocess to exist now let us look at some of the common bioreactor types some

of the ah kinds of bioreactors that are used commonly the first one that we are going to

look at is called the stirred tank bioreactor in fact this is pretty much the work hours

of the bio industry many industries use this stirred tank bioreactor as the name suggests

it is a tank which is represented by this rectangle here it is actually cylindrical

ah in reality it could be as small as something that sits on this table may be a one two liter

reactor or may be something that sits on a lab bench may be about fifteen liter reactor

to something that occupies huge spaces in the industry may be one lakh liters few lakh

liters and so on so forth that are required in some in some industries so stirred tank

all these are effectively the same except their sizes are so different all these stirred

tank reactors will have a stirrer with stirs the contents of the bioreactor and thats why

it is called a stirred tank bioreactor

it is any bioreactor for that matter is an instrumented there are various instruments

here and highly controlled kind of an environment here the typical instruments that are used

are those that are needed to measure temperature there is a thermometer or an r t d device

that measures the temperature of the bioreactor contents there are something called d o this

is not do this is d o which stands for dissolved oxygen which happens to be an important parameter

especially when we use certain kinds of micro organisms in the bioreactor p h is an important

parameter that is measured controlled ah e many bioprocesses or bioreactions take place

in a narrow range of p h the aeration happens here air is used here agitation of course

we talked about and the medium we already talked about what i would like you to wear

in mind is that the stirred tank is a vessel ok that is a bioreactor where as the actual

reactors the bioreactors or the factories that are producing the products are the cells

in the bioreactor that make these products it could be the ethanol that we talked about

the lactic acid that we talked about the m a bs that we talked about the insulin that

we talked about or the bio oil that we talked about all these are made by these microscopic

cells the size of these cells are ah anywhere between thats a two microns to ten microns

typically there could be larger too and um therefore these cells in so called culture

are the actual factories that produce a product

we need to keep this in mind when ever we look at bioreactors in the initial part of

the course we will look at the bioreactor as this vessel and do things necessary for

this vessel and this will be in the background and later towards the data part of the course

we will focus some attention on how to operate or come up with strategies based on how these

cells actually function thats what makes more sense because these cells are the actual factories

that produce products and therefore we need to have an ideas to how their doing for the

bioreactor to be effective ok this ah looking at it as sum sort of a black box may not be

very helpful in many situations so that is a stirred tank bioreactor the second type

second common type that is used is what is called an air lift bioreactor

this ah schematic shows some important features of an air lift bioreactor the main ah difference

that you would immediately notice between a stirred tank bioreactor and a air lift bioreactor

is that there is no stirrer here ok [hower/however] you need to keep the bioreactor broth in agitation

only then ah will the bioreactor function properly the agitation the mixed nature is

brought about by air which is pumped in here somewhere the air rises through this it takes

in this is a cylinder inside the reactor the air rises through this and when it rises through

this it carries the cells along with it and then it kind of circulates this is a cylinder

i hope you are able to visualize this this is one cylinder this is the outer cylinder

and therefore air rises through the center comes like this quite vigorously and because

of that it is able to keep the cells in suspension and there by the reactor operates this is

the liquid level that is shown as the dotted line here

so this is an air lift bioreactor this has some advantages over these stirred tank bioreactor

and some disadvantages we had probably look at ah some of them in the passing after we

know something more about bioreactors the third kind that i would like to present to

you is something called a packed bed bioreactor you have a bed here which is packed there

is an inlet here there is an outlet here it could be continuous typically these bio packed

bed bioreactor are operated in a continuous way and ah this is where the bioreactions

take place to convert the reactant into the desired product this is a video that you may

want to watch ah i think it is um let me go back to the packed bed fluidized bed that

is the fluidized bed i will come to that next the packed bed is just a packed bed is a stationary

bed ah which contains is organisms which convert the reactance to the products the fluidized

bed which is a variant of the packed bed would have this part fluidized fluidized in the

sense fluid like so that it will be the bed would not be stationary it will be jiggling

around jumping around and so on so forth that brings in certain desired aspects in the operation

of bioreactors and fluidized bed bioreactor are used in some situations

a packed bed bioreactor is used ah commonly in water treatment and so on so forth and

this could just be a sand bed through which ah the water to be treated flows and what

flows out of here is cleaner water another type of bioreactor is called the solid state

bioreactors as a name indicates there is typically no liquid here ok it is all solid and um this

can be used for producing ah useful substances say enzymes and so forth from natural substances

which are end of solids they could be cut down chopped on and so on forth and then place

on these trays in probably a large enclosure and appropriate conditions maintained here

and the organisms added to the appropriate sub state as these sub state is a solid ah

the organisms convert the sub state into the desired product so such a reactor is called

a solid state bioreactors they are used in the industry they were heavily used in the

industry at one point in time to produce very useful products such is enzyme they could

still be used

this is a video that would talk something about these solid state bioreactors you might

want to watch that what is become popular now a days in some industrial applications

and also in some lab applications more so in industrial applications is the use of single

use bioreactors use it throw out this has significant advantages in the process of validation

because a process of validation is rather stringent and people need to establish various

different aspects in reproducible fashion when approvals are given for the production

and approvals are given after inspections and so on so forth such operations become

significantly simplified if you can use and throw the bioreactor and therefore the single

use bioreactors are quite popular the same stirred tank could be made of a disposable

plastic vessel and ah that becomes a disposable reactor everything else remains the same even

the sizes could be reasonably large in the if you use dis disposable plastic vessels

therefore instead of this stainless steel or appropriate material ah that is used for

bioreactor construction which is a permanent there you could use disposable plastic vessels

there are advantages as we talked about earlier but there are disadvantages too um there are

some disadvantages that ah this video this you can go on take a look at that and more

recently or i think about the same time bioreactors called wave bioreactors came into being this

is also ah given in i think in the same video you can take a look at what wave bioreactors

are they are nothing but plastic bags la they could be large plastic bags with huge capacity

of twenty five liters or so ah which can be used for the production of low volume high

value products so the disposable aspect helps the validation ah maintenance and so on so

forth um and they they work they are essentially plastic bags that are kept on rockers as the

video would demonstrate and the production happens in such a condition

the next kind of bioreactor that i would like to talk about is what is called a photobioreactor

a photobioreactor means that it employees light when do we need light whenever an organism

needs light and some thing that requires light is called a photo organism photosynthetic

organism photosynthetic organisms when you use them you need to use something called

a photobioreactor remember we talked about ah micro algae for the production of ah biodiesel

micro algae happen to be photosynthetic organisms they convert the carbon dioxide in the air

to bio fuel and that is why it is also considered a carbon neutral kind of a situation that

is it doesnt take any carbon from the earth it just takes the carbon from the air converts

it into biofuel and even if it gets back into air it is still a neutral kind of a situation

there is no addition of carbon carbon dioxide from the earth into the atmosphere

so when an algae is grown micro algae is grown to produce ah bio oil you use something called

a bioreactor the process is rather straight forward and simple everything is known about

the process ah this is the vessel here which contains the broth and this vessel has an

outlet which leads to this photo section i think the next picture would show the photo

section a little better you know this is the photo section lighted up ah this is from this

angle and the second photograph is from this angle i hope you are able to understand that

is the same reactor this is taken from our lab we have we use a photobioreactor we did

some work on ah micro algae so this vessel there is an outlet which goes into the photo

section this the organisms receive light here when they are in the photo section which are

made up of glass tubes and then they return to the vessel and that happens continuously

so this is a photobioreactor coming back to the process of ah bio diesel or bio oil production

using ah micro algae the process is rather simple you grow micro algae the micro algae

ah convert the carbon dioxide in the air and in that process they accumulate lipids or

bio oil the lipids can be got in on out of the micro algae after production by pre just

pressing them using a press the oil flows out and then you can use the oil for what

ever you need

the process is very simple a lot is known about the process but the economic production

of bio oil from this route is still not happening and that is the reason why this process is

still not available commercially anywhere in the world expect on an experimental basis

may be but its not really commercially viable it has lot of promise lot of challenges some

of which we will talk about in this course those challenges are overcome then it could

be an economic reality and ah this could be a very good alternative source for bio oil

and biodiesel and many other products even jet fuel can be made from this process ok

this is the schematic of the vessel here and the photo section here this way you might

be able to understand things a little better here this contains the micro algae their let

out here there is a pump that takes it through the glass tubes in the photo section they

are exposed to light as a shown here and they come back and they photo synthesize to accumulate

bio oil this is a video that you could watch on from that list that is taken there i think

it is ah number eleven here before to bioreactor that would give you an idea is to how it is

possible to produce bio oil from micro algae through a bio process that involves a bio

reactor

and there are very many kinds of bioreactors will not possible to go through all of them

these are the common types that are used for ah producing useful products through the biological

route and you have seen some of them next let us look at the bioreactor operation modes

many of those reactors stirred tank ah air lift and the other kinds of reactors that

we saw the packed bed fluidized bed and so on they can be operated in one of three modes

three main modes the first one is a batch operation ok this is the same stirred tank

that we considered earlier and this is a stirrer here which stirs and keeps the cells and suspension

when operated when this stirred tank is operated in a batch mode what is done is we dump everything

in that is the medium the cells the inoculum so on so forth and then the reaction takes

place therefore we wait for the bio products to be made and at the end of the time we dump

everything out and proceed with further processing the downstream processing steps to separate

and purify the product from the other things

so this kind of an operation were you dump everything in wait for the process to complete

and dump everything out that kind of a process is called a batch process or a batch operation

of a bioreactor and many processes in the industry are batch is very simple ah comparatively

speaking to operate batch bioreactors compared to other types of bioreactors a kinds of operation

the next one is a continuous operation of a bioreactor the same stirred tank here you

could have a continuous input of the sub state as it is called the nutrient broth as it is

called this need not even contain any cells the cells could be here and there is a continuous

output from the bioreactor with the product made the times are adjusted so that the product

is made appropriately and such an operation is called continuous operation

what is important to note here is that during this process there is growth of cells the

product formation and the flow of nutrients all happen simultaneously ok that is important

to internalize in a continuous operation all these happen simultaneously and that internalization

is required to appropriately look at it analyse it and then use it ah probably design something

of interest to each one of you separately between these two the batch and the continuous

you have something called a fed batch operation ok it is in between the two and you could

guess what that is there could be intermittent input there could be intermittent output and

ah or both you could have some input and some output what i mean by that you start with

the probably a batch and then for some reason well known reasons you add some sub state

may be in intervals not continuously in intervals that is a fed batch you may not even remove

with anything or you could remove some part of the broth the reacting broth intermittently

that could happen or you could do both you could add intermittently and remove intermittently

and any how these kind of operations ah is called a fed batch operation and there are

various reasons for example some products that are made by this cells can be toxic to

the cells themselves simple thing is ethanol that is ah made so much ah in a so many industries

that produce ethanol and ethanol above ah some ah ten some sixteen percent or eighteen

percent is actually toxic to the cells so it cannot cannot be allowed to build up here

there are other products that could be toxic at much lower concentrations and to handle

the toxicity a part of the broth is removed and fresh broth is added so th[at]- the concentration

of the toxic product remains in check

now those were the types of bioreactors that we saw the common types and the modes of operation

of those types of bioreactors some bioreactors lend themselves to all kinds of operation

modes or all the three operation modes batch continuous and fed batch where as ah ah may

be a packed bed bioreactor or a fluidized bed bioreactor ah it may not be very easy

to operate them on may be a batch bases a continuous bases would be easier to operate

typically a continuous operation is a lot more difficult many times more effort are

required to run a continuous operation continuous batch continuous bioreactor compared to the

batch operation

ok now let us look at some other aspect we are using organisms micro oraganisms to produce

the product of our interest therefore only the organisms of interest need to be present

in that space that produces the product however organisms are present everywhere in this room

around us in the space where this bioreactor used um in hospital rooms and so on and so

forth there are organisms present in the air in reasonably large amounts and ah that is

not good for example you dont want an infectious organism that is present in the air to get

into your body ah the body has certain defense mechanism that minimize the effects ah but

still it could lead to complications thats why many of us get this infectious diseases

when the bodys defense mechanism is not able to cope more critically when a person is operated

upon when a surgery is done the persons internals are exposed and ah there is no skin or the

skin is compromised for a certain purpose for the purpose of the surgery

when the skin is compromised the organisms that are present in the air if they are present

can enter and cause infection and that should not happen and therefore the surroundings

of the surgery must be kept clean of organisms similarly the surroundings of a biorea[ctor]-

or the bioreactor itself must be clean with no organisms and then the organism of interest

alone is added to the bioreactor and that is made to multiply and produce a product

of interest therefore there is a huge need for a clean slate you might be surprised you

have a organisms to the concentration of about um ten power three cells or ten power four

cells per m l in the air around us there could be many types of organisms and you dont want

them to be present either in your body or in the bioreactor which is designed to produce

a particular type of product

what happens is if the other organisms come may be those organisms can grow much faster

than the organism of interest and that will compete with the organism for the food that

is available and the bioreactor will be a failure thats called contamination of the

bioreactor you dont want that so to avoid contamination we need a clean slate how do

we achieve this clean slate is rather interesting let us discuss this and we will close the

introduction lecture we have ah may be about nine minutes left will close the introductory

lecture with this discussion its very interesting how do you sterilize a hospital room how do

you ah remove all the organisms from a bioreactor organisms can be present anywhere corner of

the bioreactor there are three major ways in which this is done one is we use very high

temperatures may be a hundred and twenty hundred and twenty one degree c for about fifteen

minutes and a bit conditions typically used ah a high temperature can be used and that

achieves a clean slate this is been shown repeatedly it works very well

you could use chemicals liquids or vapours and that is what is typically done to sterilize

spaces such as the operation rooms or labs for example labs when we get contaminationed

then we want to remove all the organisms that are contaminating our work related organisms

and therefore what we do is we use ah formalin solution ah add potassium permanganate to

it to cause an exothermic reaction in the formality hide actually ah formality hide

vapours that come out of it kills all the cells in that space it is rather dangerous

and thats why when ah lab is sterilized there are notices put up everywhere doors are sealed

with ceiling tape the windows are sealed completely and a person of who is ah places these aluminum

boats with this formalin solution at strategic places in the lab and works out a way by which

a person can get out and seal the glass door the other doors are already sealed other windows

are already sealed and the person keeps dropping these potassium permanganate pallets into

these aluminum boats as the person walks out quickly comes out of the lab seals the door

and ah the vapours kill all the organisms no vapour is allowed to escape into outside

the lab and the lab is kept sealed for a couple of days and then you enter you can actually

smell the cleanliness or the lack of organisms in the lab along with the chemical balance

so on so forth

so this is a very common procedure for ah using chemicals ah in this case it is formalin

you could use seventy percent ethanol to kill the organisms in on your hands on your gloves

and so on so forth while working with um organisms while transferring organisms from one part

to another in a lab also you could use radiation such as u v radiation gamma radiation which

are high energy radiations that can cause changes in the ah d n a and so on so forth

of the organisms and kill the organisms when you cannot use high temperature for example

when you working with ah temperature sensitive plastics may be for syringes and so on so

forth you cannot use this high temperature process the high temperature process ah is

called autoclaving and that is used for ah substances made of ah metal such as bioreactors

ah made of metal if it is a small bioreactor you can place a whole bioreactor inside what

is called an autoclave that helps reach the conditions that we mentioned earlier one twenty

one degree c slightly elevated pressure steam because steam exists a only those conditions

if you remember thermodynamics and if that those conditions are maintained for about

fifteen minutes to half an hour then you could get a sterile space then you take that space

and make sure that the sterility is maintained and then at the right time you add the organisms

of interest that is how the autoclaving is done

if the bioreactors are large we talked of ah bioreactors that have capacities of may

be lakh few lakh liters then in situ sterilization is done you use ah similar kind of mechanisms

high temperature ah caused in place ah because you cannot move [laughter] those reactors

very easily and ah a clean slate is achieved radiation such as u v and gamma rises we mentioned

are used to treat ah or used to kill the organisms in um places where we probably cannot use

high temperature to kill or chemicals to kill so these are some of the common sterilization

methods that are used to achieve the clean slate for a bio process to begin i think we

will stop here for this lecture i think we are almost out of time ah i briefly introduced

you to this mock its a ten hour mock on bioreactors i mentioned a couple of books that you could

look at but only very loosely this organization is very different um however i will also give

you the corresponding chapters as we go through the various material some of the material

may not be there but ah whatever is there i will give you the corresponding chapters

in the books so that you can go on read the book

in the end of every week will have ah some assignment to submit mostly through multiple

choice questions however it will be good for you to develop the ah skills of problem solving

atleast close closed ended problem solving where you know everything you will have to

analyze apply and get a useful result and for that i will ah probably ah pose the problem

in one class ah give you enough time to solve it at ah after the lecture and then show you

the solution in the next class lets ah meet again in the next class