BIO204 Final Term Current Paper Spring 2021 by Amaan Khan

BIO 204 Current Final Term Spring 2021

MCQ

1-Chemostat is also known as__________________. Steady State 2A spectrophotometer is used to determine______________. Turbidity

3Spectrophotometer measuring the amount of__________. Light 4-Inlet and exist Air sterilize through ________________. Filtration 5Foam is detected by________________. Single probe level 6Which is not pH system part? Alkali delivery 7How much volume of pleated membrane filter are used in larger laboratory scale fermenter?

Up to 1000 liters

8Removal or destruction of all living organisms. Sterilization 9An ideal way sterilization media for animal culture? Filtration 10Part of fermenter? All pH/ O2 electrode Detachable stirrer motor Exhaust gas condenser 11Biology oxygen demand is abbreviated as

BOD

bod Bod BoD

Q1. How sterilization the fermenter exhaust air? 2 Marks

Q2. Which strategy adopts to remove thermal destruction of fermenter? 3 Marks

The thermal destruction of essential media components conforms approximately with first order reaction kinetics and, therefore, may be described by equations similar to those derived for the destruction of bacteria:

Therefore, the ideal technique would be to heat the fermentation medium to a high temperature, at which it is held for a short period, before being cooled rapidly to the fermentation temperature. However, it is obviously impossible to heat a batch of many thousands of litres of broth in a tank to a high temperature, hold for a short period and cool without the heating and cooling periods contributing considerably to the total sterilization time.

Q3. What is spiral heat exchanger? Write its advantages? 5 Marks

Spiral heat exchangers are also used to cool the medium after passing through the holding coil. Incoming unsterile medium is used as the cooling agent in the first cooler so that the incoming medium is partially heated before it reaches the sterilizer. The major advantages of the spiral heat exchanger are: i. The two streams of medium and cooling liquid, or medium and steam, are separated by a continuous stainless-steel barrier with gasket seals being confined to the joints with the end plates. This makes cross contamination between the two streams unlikely. ii. The spiral route traversed by the medium allows sufficient clearances to be incorporated for the system to cope with suspended solids. The exchanger tends to be self-cleaning which reduces the risk of sedimentation, fouling and 'burningon'.

Q4. How many types reactions are involved in filtration during sterilization? 5 Marks

Two types of reaction contribute to the loss of nutrient quality during sterilization: i. Interactions between nutrient components of the medium. A common occurrence during sterilization is the Maillard type browning reaction which results in discoloration of the medium as well as loss of nutrient quality. These reactions are normally caused by the reaction of carbonyl groups, usually from reducing sugars, with the amino groups of amino acids and proteins. An example of the effect of sterilization time on the availability of glucose in a corn-steep liquor medium is shown in Table (in next slide). Problems of this type are normally resolved by sterilizing the sugar separately from the rest of the medium and recombining the two after cooling. ii. Degradation of heat labile components. Certain vitamins, amino acids and proteins may be degraded during a steam sterilization regime. In extreme cases, such as the preparation of media for animal cell culture, filtration may be used.