Biotechnology: Principles and Processes: Class 12 Biology Chapter 9 Hinglish mein

Kisi bhi chemist ki dukaan ka medicine fridge kholo, to wahan shayad human insulin ki vials milengi. Unke andar ka insulin kisi insaan se nahi liya gaya tha. Use un microbes ne banaya jo human insulin gene ki ek copy carry karte hain, aur jinhe steel tanks mein tonnon ke hisaab se ugaya jaata hai. Yeh chapter un do ideas ko samjhata hai jo aisa product possible banate hain: scientists ek chuna hua gene naye host mein kaise daalte hain, aur us host ko bade scale par kaise ugaate hain aur woh jo banata hai use kaise nikaalte hain.

Sabse broad sense mein, biotechnology (जैव प्रौद्योगिकी) living cheezon ka, ya unse liye gaye enzymes ka, koi bhi aisa use hai jisse hum apni chahi cheez banayein ya koi kaam karwayein. Is paimaane se dekho to Indian kitchens sadiyon se ise karte aa rahe hain: microbes doodh ko dahi banate hain aur idli batter ko phulaate hain. Lekin aaj jab scientists biotechnology ki baat karte hain, to unka matlab aksar aise kaam se hota hai jo un organisms par based hai jinke genes jaan-boojh kar badle gaye hain, aur jo factory scale par chalta hai. Modern field mein IVF ('test-tube' babies), lab mein jode gaye genes, DNA vaccines aur gene therapy, jo kharab gene ko theek karti hai, jaisi techniques bhi aati hain.

European Federation of Biotechnology ek aisi definition deti hai jo dono tarah ko cover kar le. Apne shabdon mein kahein to yeh biotechnology ko natural science ko organisms, unke cells ya cell parts, aur unki molecular copies ke saath jodna batati hai, taaki goods aur services banaye ja sakein.

9.1 Biotechnology ke Principles

Modern biotechnology do techniques par khadi hai. Ek yeh badalti hai ki organism kya hai; doosri us badle hue organism ko bahut badi sankhya mein ugane deti hai, bina uske saath kuch aur ugne diye.

• Genetic engineering genetic material ko dobara likhti hai. Ek gene (DNA, ya kabhi-kabhi RNA) ko badla jaata hai ya host organism mein daala jaata hai, aur phir host ek naya character dikhata hai.
• Bioprocess engineering bahut badi, germ-free cultures ki engineering hai. Yeh ek chune hue cell type, microbial ya eukaryotic, ko bahut badi sankhya mein ugaati hai, bina kisi contaminating microbe ke, taaki antibiotics, enzymes, vaccines aur aise hi products banaye ja sakein.

Jab breeders pehle se plants aur animals ko cross karte hain, to itni mehnat kyun? Sexual reproduction genes ko phir se mila deta hai aur isse useful variety banti hai, jabki asexual reproduction genome ko waisa hi rakhta hai. Lekin cross ek-ek karke genes nahi chun sakta. Jab breeder ek helpful gene paane ke liye crop ko uske wild relative se cross karta hai, to wild chromosome ke lambe hisse bhi saath aa jaate hain, jinmein aksar aise genes hote hain jo koi nahi chahta (Fig. 9.1). Genetic engineering isse bachti hai: yeh sirf wahi gene, ya genes ka chhota set, isolate karti hai jo hum chahte hain aur sirf use target organism mein daalti hai.

Foreign gene ko origin of replication kyun chahiye

Cell apne DNA ki copy sirf khaas starting points se banata hai. Har chromosome aur har plasmid mein aisa ek sequence hota hai, jise origin of replication ya ori kehte hain, aur poore molecule ki copying wahin se shuru hoti hai. Genetic engineering ke liye iska seedha asar hai. Foreign DNA ke khule fragment mein ori nahi hota, isliye jo bacterium use le leta hai woh uski copy nahi banata; kuch divisions ke baad woh dilute hokar khatam ho jaata hai ya toot jaata hai. Wahi fragment kisi plasmid ya chromosome se jod do, to jab bhi uska partner copy hota hai woh bhi copy hota hai aur har daughter cell tak pahunchta hai (Fig. 9.2). Is tarah kisi DNA segment ki bahut saari identical copies banana use cloning karna kehlaata hai.

Pehla recombinant DNA

Stanley Cohen aur Herbert Boyer ne 1972–73 mein jo banaya, woh asal mein ek extra gene carry karne wala plasmid tha: ek aisa gene jo bacteria ko ek antibiotic ke against resistant banata tha. Gene ko us plasmid se nikaalne ke liye jismein woh naturally tha, unhone ek aisa enzyme use kiya jo DNA ko sirf ek khaas sequence par kaatta hai, yaani restriction enzyme (jise aksar molecular scissors kehte hain). Phir kate hue gene ko DNA ligase ki madad se ek chhote natural plasmid mein jod diya gaya, jo tumhari textbook ke hisaab se Salmonella typhimurium se aaya tha; DNA ligase woh enzyme hai jo kate DNA ends ko seal karta hai. Is product, yaani pehle artificial recombinant DNA, ko poori tarah test tube mein joda gaya tha, phir bhi woh kisi natural plasmid ki tarah apni copy bana sakta tha.

Is experiment mein plasmid ne vector ka kaam kiya, yaani host mein DNA pahunchane wala carrier; ise ek courier van samjho jo parcel sahi address par le jaati hai. Host ke roop mein Escherichia coli chuna gaya, jo Salmonella ka kareebi rishtedaar hai. Andar pahunchne ke baad recombinant plasmid ko kisi khaas madad ki zaroorat nahi thi: bacterium ka apna DNA polymerase har division par uski copy banata tha, is tarah resistance gene E. coli mein clone ho gaya (Fig. 9.3).

Details hata do to har genetic modification, chahe microbe ki ho, crop ki ya animal ki, ke liye teen cheezein sahi honi chahiye:

1. move karne laayak gene ko dhoondho aur us DNA ko isolate karo jismein woh hai;
2. use naye organism mein pahunchao;
3. use wahan tikaao, taaki woh host mein bana rahe aur host ki aane wali peedhiyon ko mile.

9.2 Recombinant DNA Technology ke Tools

Recombinant DNA ke kaam ke liye tools ka ek chhota kit chahiye, aur har tool ka ek hi kaam hai. Lagbhag sabhi ko microbes ne apne kaam ke liye banaya tha, aur humne bas unhe udhaar le liya hai.

• Restriction enzymes DNA ko chune hue sequences par kaatte hain.
• DNA polymerases DNA ko copy karte hain, cell mein ya tube mein.
• DNA ligases DNA ke kate pieces ko jodte hain.
• Vectors gene ko host mein le jaate hain aur wahan uski copy banwaate hain.
• Ek host organism, aksar ek bacterium, DNA ko le leta hai aur use badhaata hai.

9.2.1 Restriction Enzymes

Bacteria par bacteriophages lagatar hamla karte rehte hain; yeh aise viruses hain jo apna DNA cell mein inject karte hain. 1963 mein unki defence ka pata E. coli ke do enzymes ke pair tak chala. Ek, methylase, bacterium ke apne DNA par methyl groups ka tag lagata hai. Doosra ek nuclease hai jo bina tag wale DNA ko kaatta hai, isliye hamla karne wale phage ka genome kabza karne se pehle hi tukdon mein kat jaata hai. Kyunki yeh virus ki growth ko restrict karta hai, is kaatne wale enzyme ka naam restriction endonuclease rakha gaya.

Pehla restriction enzyme jiski cutting ek khaas base sequence se judi paayi gayi, Hind II, lagbhag paanch saal baad isolate aur study kiya gaya. Use koi bhi DNA diya jaaye, woh ek hi tarah ki jagah par kaatta tha: ek fixed sequence wala chhe base pairs ka hissa. Aise hisse ko enzyme ka recognition sequence kehte hain. Jab tak tumhari textbook likhi gayi, 230 se zyaada bacterial strains mein 900 se zyaada alag restriction enzymes mil chuke the, har ek ka apna recognition sequence, aur yeh list abhi bhi badh rahi hai.

Enzyme ka naam ek chhota sa address hota hai. EcoRI ko lo. E genus Escherichia ke liye hai aur co species coli ke liye; yeh teen letters italics mein chhapte hain. R strain RY13 ko batata hai, aur Roman numeral I batata hai ki yeh us strain se isolate hua pehla enzyme tha. Har restriction enzyme ka naam isi plan par rakha jaata hai: genus ka pehla letter, species ke do letters, zaroorat ho to strain code, aur phir discovery ka order.

Chemically restriction enzyme ek nuclease hai: yeh un bonds ko todta hai jo ek nucleotide ko agle se jodte hain. Nucleases mein farak is baat ka hai ki woh DNA par kahan attack karte hain.

Palindromes aur sticky ends

Ek enzyme laakhon base pairs mein se chhe khaas base pairs kaise dhoondhta hai? Yeh double helix ke saath-saath chalta hai, sequence check karta hai, aur sirf wahin rukta hai jahan uska recognition sequence hota hai. Phir yeh dono strands ke sugar–phosphate backbone ko fixed positions par todta hai. Zyaadatar recognition sequences palindromes hote hain. 12321 jaisa number dono taraf se same padha jaata hai; DNA palindrome thoda alag hai, kyunki uske do strands opposite directions mein chalte hain. Har strand ko uske 5′ end se 3′ end tak padho, to dono same sequence dete hain. EcoRI ke liye site top strand par GAATTC hai, aur bottom strand ko uski apni 5′→3′ direction mein padhne par bhi GAATTC milta hai.

Dekho EcoRI backbone ko kahan todta hai (Fig. 9.4). Har strand par yeh G aur A ke beech ka bond kaatta hai, isliye dono breaks aamne-saamne nahi balki chaar bases ki doori par hote hain. Jab dono halves alag hote hain, to har end par ek chhoti single-stranded tail, AATT, reh jaati hai. Aise ends ko sticky ends (चिपचिपे सिरे) kehte hain. Ek hi enzyme se bane koi bhi do ends ki tails complementary hoti hain, isliye woh ek doosre ko dhoondh kar hydrogen bonds se pair kar lete hain. Pair hue ends dheele se jude rehte hain, aur har backbone mein ek break (nick) bacha rehta hai; DNA ligase in nicks ko covalent bonds se band karta hai. SmaI jaise kuch enzymes dono strands ko ek hi point par kaatte hain aur blunt ends chhodte hain, jinhe ligase jod to sakta hai, lekin kam efficiently.

Isse ek practical rule nikalta hai. Ek enzyme chuno (ya aisa pair jo identical tails chhode) aur use apne gene wale DNA aur vector, dono par use karo. Mismatched enzymes ki tails pair nahi kar sakti, aur recombinant molecule nahi banega.

Fragments ko alag karna aur wapas nikaalna

Digest ke baad alag-alag lengths ke DNA fragments ka mixture bachta hai, aur unhe gel electrophoresis se chhaanta jaata hai. Agarose se bani jelly ki ek slab socho; agarose seaweeds se milne wala ek polysaccharide hai. Andar se yeh fibres ka uljha hua jaal hai. DNA mixture ko ek end par chhote wells mein rakha jaata hai aur electric field on kiya jaata hai. Har fragment ke phosphate groups par negative charges hote hain, isliye sab anode (+) ki taraf chalte hain. Chhote pieces jaal se aasaani se nikal jaate hain; lambe baar-baar atakte hain. Kuch der baad fragments size ke hisaab se phail jaate hain, aur sabse chhote wells se sabse door hote hain (Fig. 9.5).

Tank se seedha nikla gel khaali dikhta hai, kyunki DNA colourless hota hai. Use ethidium bromide jaise dye mein bhigoya jaata hai, jo base pairs ke beech ghus jaata hai, aur ultraviolet light ke neeche rakha jaata hai; ab har band orange glow karta hai. Jo band chahiye use blade se kaat kar nikaala ja sakta hai, aur us slice ka DNA dho kar purify kiya jaata hai. Gel slice se is tarah DNA wapas nikaalne ko elution kehte hain. Nikaala gaya fragment cloning vector se jodne ke liye taiyaar hai.

9.2.2 Cloning Vectors

Genes ka carrier tab sabse useful hai jab host uski copy baar-baar banaye. Plasmids aur bacteriophages dono is par khare utarte hain, kyunki bacterium unki copy apne chromosome se alag banata hai. Har ek ka ek typical copy number hota hai, yaani per cell copies ki sankhya. Phages ke liye yeh bahut zyaada hota hai. Plasmids mein yeh kaafi alag-alag hota hai: kuch sirf ek-do copies mein rehte hain, jabki doosre 15 se 100 ya usse bhi zyaada copies tak pahunchte hain. Aise carrier mein gene jodo, to gene ka bhi wahi copy number ho jaata hai. Aaj ke cloning vectors (संवाहक) is kaam ke liye nayi design wale plasmids ya phages hain: inmein foreign DNA daalna aasaan hai aur un cells ko dhoondhna bhi aasaan hai jinmein insert pahuncha.

Chaar features vector ko useful banate hain.

(i) Origin of replication. Vector ki copying uske ori se shuru hoti hai, isliye vector se juda gene bhi copy hota hai. Ori yeh bhi tay karta hai ki har cell vector ki kitni copies rakhega. Isliye agar gene ko badi maatra mein paana hai, to use high-copy ori wale vector mein clone karo.

(ii) Selectable marker. Jab bacteria ko vector ke saath mix kiya jaata hai, to sirf ek chhota hissa use le paata hai. DNA lene ke process ko transformation (रूपांतरण) kehte hain, aur jo cells safal hote hain woh transformants kehlaate hain. Baaki sabse chhutkara paane ke liye vector ek selectable marker carry karta hai, yaani aisa gene jo sirf use rakhne wale cells ko ek khaas medium par zinda rehne deta hai. E. coli mein sabse pasandida markers antibiotic-resistance genes hain, jaise ampicillin, kanamycin, tetracycline ya chloramphenicol ke against. Normal E. coli mein aisi koi protection nahi hoti, isliye antibiotic har us cell ko maar deta hai jismein vector nahi hai.

(iii) Cloning sites. Foreign DNA wahan daala jaata hai jahan restriction enzyme vector ko kholta hai. Agar enzyme vector ko do ya teen jagah kaat de, to vector tukdon mein bikhar jaayega jinhe phir sahi order mein wapas jodna padega, jo lagbhag namumkin kaam hai. Isliye achhe vectors mein har aam enzyme ki sirf ek recognition site hoti hai, ya zyaada se zyaada bahut kam. Classic E. coli vector pBR322 yeh features dikhata hai (Fig. 9.7).

Insert carry karne wali colonies kaise dhoondhoge? pBR322 mein do resistance genes hain, aur uski BamHI site tetracycline-resistance gene ($te{t}^R$) ke andar hai. BamHI par daala gaya gene $te{t}^R$ ko tod deta hai, lekin ampicillin-resistance gene ($am{p}^R$) ko kaam karta chhod deta hai. Isliye transformed bacteria ko pehle ampicillin wali plate par phailaya jaata hai, jahan sirf woh cells colonies banate hain jinhone plasmid liya, insert ke saath ya bina. Phir ek velvet pad colonies ko, har ek ko uski apni position par, tetracycline wali plate par copy karta hai. Jo colonies dono plates par dikhti hain unmein khaali plasmid hai. Jo colonies ampicillin par ugi lekin tetracycline par gayab hain, woh recombinants hain (Fig. 9.8). Short mein, ek marker transformants ko select karta hai, aur doosra, jise insert band kar deta hai, recombinants ko pehchaanwata hai.

Kuch plates par colonies do rang ki hoti hain, blue aur white. Yeh ek tez trick hai jismein sirf ek plate chahiye. Yahan vector ki cloning site enzyme β-galactosidase ke gene ke andar hoti hai, aur medium mein ek colourless chromogenic substrate hota hai jise yeh enzyme blue kar deta hai. Jis colony ke plasmid mein insert nahi hai, woh enzyme banati hai aur blue ho jaati hai. Jis colony ke plasmid mein insert aa gaya, usmein gene insertional inactivation se toot jaata hai, enzyme nahi banta aur colony white rehti hai. Bas white colonies utha lo (Fig. 9.9).

Plants aur animals ke liye vectors

Plants aur animals mein genes pahunchane ke liye scientists ne experts ki nakal ki: pathogens. Agrobacterium tumefaciens ek soil bacterium hai jo kai dicot plants mein crown gall karta hai. Isme ek bada Ti plasmid (tumour-inducing plasmid) hota hai, aur is plasmid ka ek hissa, T-DNA, sach mein plant cell mein jaata hai aur plant chromosome ka hissa ban jaata hai. T-DNA ke genes cell ko divide karwaakar ek tumour, yaani crown gall, banwaate hain, aur use khaas chemicals, opines, banane par majboor karte hain jinhe bacterium khaata hai (Fig. 9.10).

Is delivery system ko safely use karne ke liye Ti plasmid ko disarm kiya gaya hai. Tumour paida karne wale genes nikaal diye gaye aur transfer machinery rehne di gayi, isliye T-DNA borders ke beech rakha koi bhi gene ab bina bimaari ke plant cells mein pahunchta hai. Animals ke apne natural gene couriers hain, retroviruses, jo normal cells ko cancerous bana sakte hain; disarmed retroviruses ka use useful genes ko animal cells mein laane ke liye hota hai. Humein jo bhi host chahiye, bacterium, plant ya animal, ab uske liye ek vector hai jo cloned gene ko usmein le ja sakta hai.

9.2.3 Competent Host (Recombinant DNA se Transformation ke liye)

Bacterium apne aas-paas se DNA ko seedha kyun nahi sokh leta? DNA hydrophilic hai aur us par bahut saare negative charges hain, jabki cell membrane ka core oily aur paani ko repel karne wala hota hai, isliye DNA apne aap usse paar nahi ho sakta. Isliye bacteria ko pehle competent banaya jaata hai. Aam trick hai unhe ek divalent cation ke solution mein bhigona, aksar calcium chloride se mila calcium, dhyaan se chuni concentration par; isse DNA ke liye cell envelope ke pores se andar jaana kaafi aasaan ho jaata hai.

Baaki kaam temperature ka hai. Competent cells aur recombinant DNA ko mix karke ice par thanda kiya jaata hai. Phir tube ko heat shock diya jaata hai: thodi der ke liye, aksar 30–90 seconds, lagbhag 42 °C, aur phir seedha wapas ice par. Is chhote jhatke ke dauraan plasmid kuch cells mein ghus jaata hai (Fig. 9.11).

Doosre hosts ko doosre methods chahiye. Animal cells mein DNA micro-injection se daala ja sakta hai: baal se bhi kahin patli glass needle recombinant DNA ko seedha cell ke nucleus mein pahunchati hai. Plant cells ki deewaarein mazboot hoti hain, isliye unpar aksar biolistics (gene gun) chalaya jaata hai: gold ya tungsten ke microscopic beads par DNA ki coating karke unhe tez speed se cells mein daaga jaata hai. Teesra raasta ek disarmed pathogen bhejta hai, jaise Agrobacterium ya modified virus, jo cell ko infect karte hue recombinant DNA pahuncha deta hai.

9.3 Recombinant DNA Technology ke Processes

Tools haath mein aane ke baad ek recombinant DNA project steps ke ek fixed sequence se guzarta hai, kachche tissue se lekar bottle mein band product tak.

9.3.1 Genetic Material (DNA) ka Isolation

Restriction enzymes nakhre wale hote hain: unhe saaf DNA chahiye, cell ke contents ka soup nahi. Lekin living cell mein DNA ek membrane ke peeche hota hai, aur bacteria, plants aur fungi mein ek wall ke peeche bhi. Isliye pehle cells ko toda jaata hai, jisse sab kuch ek saath bahar aa jaata hai: DNA, lekin saath mein RNA, proteins, lipids aur polysaccharides bhi. (Lagbhag har organism ka genetic material DNA hai; sirf kuch viruses iski jagah RNA use karte hain.)

Har tarah ki wall ka apna enzyme hai: lysozyme bacterial cells ko kholta hai, cellulase plant cells ko aur chitinase fungal cells ko. Phir unwanted molecules ko ek-ek class karke hataya jaata hai. Ribonuclease (RNase) RNA ko digest karta hai. Protease proteins ko digest karta hai, un histones ko bhi jinke charon taraf DNA lipta hota hai. Aur treatments baaki contaminants ko hata dete hain. Aakhir mein ice-cold ethanol daala jaata hai. DNA ismein insoluble hai, isliye purified DNA solution se baarik white dhaagon ke dher ki tarah bahar aata hai, jinhe glass rod par lapet kar nikaala ja sakta hai; ise spooling kehte hain (Fig. 9.12).

9.3.2 Specific Locations par DNA ki Cutting

Har restriction enzyme ki apni pasandida working conditions hoti hain, ek khaas buffer, salt level aur temperature (aksar 37 °C). Purified DNA ko un conditions mein enzyme ke saath incubate kiya jaata hai. Kaise pata chalega ki cutting ho gayi? Beech-beech mein mixture ka thoda hissa lo aur use agarose gel par run karo: negatively charged hone ki wajah se DNA anode ki taraf chalta hai, aur jaise-jaise digest aage badhta hai, uncut DNA ka akela band fragments ke bands mein badal jaata hai (Fig. 9.5). Vector ko bhi isi tarah khola jaata hai, aam taur par usi enzyme se.

Ab dono kate hue DNAs ko saath laaya jaata hai. Gene of interest wale fragment ko khule vector ke saath mix kiya jaata hai aur DNA ligase daala jaata hai; matching sticky ends pair karte hain, ligase unhe seal karta hai, aur recombinant DNA ban jaata hai.

9.3.3 PCR se Gene of Interest ka Amplification

Kabhi-kabhi jo gene chahiye woh sirf kuch copies mein hota hai, kaatne aur clone karne ke liye bahut kam. Polymerase chain reaction (PCR) is problem ko hal karta hai: yeh DNA ke ek chune hue hisse ko test tube mein baar-baar copy karta hai. Reaction mein template DNA, do primers (DNA ke chhote, chemically banaye gaye single strands jo target region ke dono ends se match karte hain), chaaron deoxynucleotides aur ek DNA polymerase hota hai. Har bound primer ke end se shuru karke polymerase ek-ek karke nucleotides jodta hai, aur har nucleotide template strand se pair karne ke liye chuna jaata hai.

Ek cycle teen temperatures se guzarta hai, jinhe thermal cycler naam ki machine control karti hai (Fig. 9.13).

1. Denaturation (lagbhag 94 °C): garmi DNA ke do strands ko alag kar deti hai.
2. Annealing (lagbhag 50–60 °C, primers par depend karta hai): dono primers target ke dono taraf, har strand par ek, apne matching sequences se jud jaate hain.
3. Extension (72 °C): polymerase har primer se template ko copy karte hue naya strand banata hai.

Har denaturation step ki garmi polymerase ko khatam kyun nahi kar deti? Kyunki PCR mein ek thermostable enzyme, Taq polymerase, use hota hai, jo Thermus aquaticus se aata hai, ek bacterium jo garam paani ke chashmon mein rehta hai. Yeh baar-baar garam hone par bhi bach jaata hai, isliye ek dose poore run ke liye kaafi hai. Ek cycle mein bana har naya strand agle cycle mein template ka kaam karta hai, isliye copies ki sankhya har cycle mein lagbhag double ho jaati hai, aur lagbhag 30 cycles ek single molecule ko lagbhag ek billion bana dete hain. Agar gene ko clone karna hai, to in copies ko kisi bhi doosre DNA fragment ki tarah vector mein joda ja sakta hai.

9.3.4 Host Cell/Organism mein Recombinant DNA ka Insertion

Agle step ko ek sorting problem ki tarah socho. Competent E. coli ki ek tube ko ligated DNA ke saath mix kiya jaata hai, Section 9.2.3 ke kisi method se, aur sirf kuch cells plasmid andar le paate hain. Maan lo plasmid mein ampicillin-resistance gene hai. Poori tube ko ampicillin wale agar par phailao: bina plasmid wale cells mar jaate hain, jabki plasmid wala har cell, jo ab resistant hai, ugkar colony banata hai. Yeh gene selectable marker ka kaam kar raha hai. Phir ek doosra test, jaise tetracycline par plating ya blue–white screening, recombinants ko khaali vector wale cells se alag karta hai (Fig. 9.8, Fig. 9.9).

9.3.5 Foreign Gene Product haasil karna

Gene ki copy banana shayad hi kabhi aakhri goal hota hai; lagbhag hamesha maksad woh protein hota hai jiske liye gene code karta hai. Iske liye host ko gene express karna padta hai, yaani use transcribe karna aur message ko translate karna. Foreign host mein expression ek technical kala hai: gene ko sahi control signals chahiye, aur growth conditions ko use on karna chahiye. Kisi doosri species, yaani heterologous host, mein express hue gene se bana protein recombinant protein kehlaata hai. E. coli ya yeast mein bana human insulin iska example hai.

Lab mein in cells ka ek flask itna protein de deta hai ki use extract, purify aur study kiya ja sake. Lekin ek medicine ki zaroorat laakhon patients ko ho sakti hai, aur flask jitne cultures uske aas-paas bhi nahi pahunch sakte. Production ko scale up karna padta hai.

Yield badhane ka ek tarika continuous culture hai. Fresh medium lagatar andar aata hai, aur utna hi used medium, kuch cells ke saath, bahar nikalta hai. Cells ka khaana kabhi khatam nahi hota aur waste jama nahi hota, isliye woh apne sabse productive, exponential (log) phase of growth mein rehte hain aur akele batch ko poora chalne dene se zyaada biomass, aur zyaada protein, dete hain.

Scale up karne ke liye bioreactors chahiye. Bioreactor ek aisa vessel hai jismein living cells ka culture, bacteria ya yeast ya plants, animals ya humans ke cells, saste raw materials ko kisi chune hue product, jaise protein ya enzyme, mein badalta hai. Tumhari textbook 100–1000 litres wale vessels batati hai; industrial tanks aksar kahin bade hote hain. Sabse zaroori baat, bioreactor ko cells ke liye ideal conditions banaye rakhni chahiye: kaafi oxygen aur nutrients (substrate, salts aur vitamins), aur sahi pH aur temperature.

Zyaadatar bioreactors stirred-tank type ke hote hain (Fig. 9.15). Tank ek cylinder hota hai, ya uska bottom gol hota hai, kyunki curved surfaces mein koi dead corners nahi bachte jahan culture ruka reh sake. Ek motor central shaft par lage impellers ko ghumata hai, jisse broth ek jaisa rehta hai aur oxygen uske har hisse tak pahunchti hai. Sparged stirred tank mein sterile air bhi bottom par ek chhedon wali ring (sparger) se andar phoonki jaati hai; bahut saare chhote bubbles ek bahut bada total surface dete hain jisse oxygen ghulti hai. Vessel ke charon taraf woh systems hote hain jo cells ko aaram mein rakhte hain: agitator aur air (oxygen) supply, temperature ko steady rakhne wala water jacket, acid ya alkali daalne wale pumps se juda pH probe, ek foam breaker, aur sampling ports jinse culture ki thodi maatra bina microbes ko andar aane diye nikaali ja sakti hai.

9.3.6 Downstream Processing

Run ke aakhir mein tank mein product cells, used medium aur by-products ke saath mila hota hai, pharmacy shelf ke liye bilkul taiyaar nahi. Iske baad ka kaam, mainly product ko alag karna aur purify karna, downstream processing (अनुप्रवाह संसाधन) kehlaata hai. Phir purified product ko formulate kiya jaata hai, jaise preservatives ke saath injection banana jo use stable rakhein. Kisi bhi doosri drug ki tarah, nayi medicine ko clinical trials paas karne padte hain, aur har batch ko strict quality control tests clear karne padte hain. Koi ek recipe sab products par fit nahi hoti: har product ko apne downstream steps aur tests chahiye.