Microbial Biomass ProductionMujtaba ChaudhryMalik Murtaza Khan KasiSanila Shamsi

Mujtaba Chaudhry

• Main Aim is the conversion of substrate into a useful primary or secondary metabolic product as shown below:

AlcoholsOther products.Organic AcidsAntibiotics

Two Types of production• 1. Production of Target Products :• as mentioned in last diagram where when once

optimal amount of target product is once achieved the organisms produced are merely waste materials that have to disposed safely at a cost.

• 2. Dedicated Biomass production: • The cells produced during the fermentation

process are the products themselves.

Use of Microbial Biomass1. viable microbial cells are prepared as fermentation starter cultures and inocula for food and beverages.2. as a source of protiens.3. animal fodder.

• Microbial proteins constitute a minor portion in Human diets

• comes from edible microfungi and truffles

• and a small portion from yeast present in bread i.e 2g per week. Per person.

Skimming Method for yeast production• Oldest and easy method for yeast production is

“Skimming Method” by S. Cerevisiae.• Skimming method involved media derived from

cereal grains.• Yeast floated on top and skimmed off, washed and

press dried.• After WW1 shortage of cereal lead to alternative

media usage. In which ammonia, ammonium salts and molasses was used.

Manufacture of Baker’s Yeast

Starter culture

• Originates from pure freeze-dried sample or agar medium culture.

• Yeast cells transferred to smaller liquid culture flasks then to larger intermediate flasks and then to large fermenters for 50,000 to 350,000 litres production

Constituents

• Molasses as carbon and energy source which is pretreated with acid to remove sulphides and heated to precipitate proteins.

• Molasses is often deficient in amino acids so supplementation with biotin etc. pH 4-4.4

Aeration

• To increase yeild.• for 30 mins to ripen yeast cells in end when nutrients

deplete.

Desirable Feautures of Baker’s Yeast1. High glycolytic activity 2. Rapid utilization of maltose3. Osmotolerance4. Good storage characteristics.5. High growth rates.

Mushrooms• Edible mushrooms and their fruiting bodies.• Good source of proteins• Some are toxic and have narcotic effects.• Involves solid substrate production.• Several advantages in exploitation of such fruiting

fungi for generation of edible biomass.

Agaricus bisporus• 90% of total mushroom production value. • Crop produced within 6 weeks.• Decomposers of cellulosic bodies.• naturally found in woodlands and meadows.• A. bitorquis is also grown which is less prone to

certain viruses and bacterial blotch disease of fungi.

Agaricus production1. Inoculation preparation2. Solid-substrate preparation3. Substrate sterilization4. Spawn Inoculation5. Casing layer of peat6. Fruiting body production

Specialty Mushrooms• China is the major producer• Lentinula edodes (Shiitake) one of most favourite

and special mushrooms.• Others are, Maitake, Enokitake etc.• Production on modern synthetic logs is much

quicker.

Sanila Shamsi

Single cell protein Scp includes whole cell of bacteria, yeast etc

containing carbohydrates , lipids , vitamins and mineral salts

Advantages

• rapid growth rate and high productivity;• high protein content, 30–80% on a dry weight

basis;• the ability to utilize a wide range of low cost

carbon sources.• strain selection and further development are

relatively straight forward,;

• the processes occupy little land area;• production is independent of seasonal and climatic variations; and• consistent product quality.

many filamentous fungi have a capacity to degrade a wide range of

materials and, like yeasts, can tolerate a low pH, which reduces the

risk of microbial contamination. They are also more easily harvested

at the end of fermentation than yeasts or bacteria

PRODUCTION OF SCPCharacteristics kept in mind before choosing

strain;

• performance (growth rate, productivity and yields)

• on the specific, preferably low-cost, substrates to be used

• temperature and pH tolerance;• oxygen requirements, heat generation during

fermentation and foaming characteristics

.• growth morphology and genetic stability in the

fermentation;• ease of recovery of SCP and requirements for

further downstream processing.• structure and composition of the final product, in

terms of protein content, amino acid profile, RNA level,flavour, aroma, color and texture.

SCP ProcessMedium preparation

The main carbon source may require physical or chemical pretreatment prior to use. Polymeric substrates are often hydrolyzed before being incorporated with sources of nitrogen, phosphorus and other essential nutrient.

Fermentation. The fermentation may be aseptic or run as a

‘clean’ operation depending upon the particular objectives. Continuous fermentations are generally used, which are operated at close to the organism’s maximum growth rate (max), to fully exploit the superior productivity of continuous culture.

Separation and downstream processing.

Processed in order to reduce the level of nucleic acids.

Involves a thermal shock to inactivate cellular proteases.

Depending upon the growth mediumused, further purification may be required, such as

asolvent wash, prior to pasteurization, dehydration

andpackaging.

Malik Murtaza Khan Kasi

Processes1. The Bell process2. The Symba process3. The Pekilo process4. The Bioprotein process5. The Pruteen process

The Bell process• History reduce the pollution of diary industry• YIELD over 80 million per anum• High Capital cost High COD• Efficiency of Whey45g/L lactose and 10g/L protein• lactose utilizing Yeast• Final product , Protible.

Process• Whey pasteurization• Lactose concentration • Addition of mineral salts• Appropriate conditions• Biomass production• recovery of Yeast.

Symba process• Aim and Objectives• Problem Not Economically Attractive high proportion of starch • SolutionSymbiotic associationSaccharomycopsis fibuligeriaCandida utilis

Process • Two stage process1st stage Rate limiting stepS.fibuligeria grown in small reactorsUnder sterilized conditions with N and P supply.2nd stageSymbiotic reactionC.Utilis constitutes the final product• Refining of final product.

The Pekilo process• Aim and objectiveProduction of filamentous fungusUtilization of spent sulphite liqour• Process Addition of supplimentsInoculation with paecilomyces variotii• Production10000 tons of SCP per year from 2 fermentersPekilo protein 59% crude protein.

BioProtein process• Production from saturated hydrocarbons• Mostly used in 1960s and 1970s • ProblemsImmiscible in waterRequire purification or protein product treatedCoolingAeration

Process • Methane rich natural gas• Heterotrophic bacteria• Continuous fermentation• Loop fermentor containing NH3, minerals and

methane• Final product pronin 70% protein• Importance Fish and animal food and in future may be used in humans food.

The Pruteen process• Uses Methanol instead of Methane• SignificanceMiscible in waterResultant protein do not require purificationHigh yield• ProblemsLow tolerance by m/oHigh heat of fermentationOxygen requirement is high.

History • Role of ICI in EUUsed methylotrophic bacterium M.methylotrophus for the production of feed for chicken, pigs called Pruteen

Process • Worlds largest continuous aerobic bioprocess

system• Cycle air lift fermentor with inner loop (3000m3)• Fluid volume of 1.5 *10^6 L• Capable of producing 50000 tonnes pruteen per

anum• Costs of fermenter