Microbial Biomass Production Mujtaba Chaudhry Malik Murtaza Khan Kasi SanilaShamsi
Main Aim is the conversion of substrate into a useful primary or secondary metabolic product as shown below:
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 Biomass 1. 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.
Desirable Feautures of Baker’s Yeast • High glycolytic activity • Rapid utilization of maltose • Osmotolerance • Good storage characteristics. • 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.
Agaricusbisporus • 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 production • Inoculation preparation • Solid-substrate preparation • Substrate sterilization • Spawn Inoculation • Casing layer of peat • Fruiting body production
Specialty Mushrooms • China is the major producer • Lentinulaedodes(Shiitake) one of most favourite and special mushrooms. • Others are, Maitake, Enokitake etc. • Production on modern synthetic logs is much quicker.
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 SCP Characteristics 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 Process Medium 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 medium used, further purification may be required, such as a solvent wash, prior to pasteurization, dehydration and packaging.
Processes • The Bell process • The Symba process • The Pekilo process • The Bioprotein process • 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 Whey 45g/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 • Solution Symbiotic association Saccharomycopsisfibuligeria Candida utilis
Process • Two stage process 1st stage Rate limiting step S.fibuligeriagrown in small reactors Under sterilized conditions with N and P supply. 2nd stage Symbiotic reaction C.Utilis constitutes the final product • Refining of final product.
The Pekilo process • Aim and objective Production of filamentous fungus Utilization of spent sulphiteliqour • Process Addition of suppliments Inoculation with paecilomycesvariotii • Production 10000 tons of SCP per year from 2 fermenters Pekilo protein 59% crude protein.
BioProtein process • Production from saturated hydrocarbons • Mostly used in 1960s and 1970s • Problems Immiscible in water Require purificationor protein product treated Cooling Aeration
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 • Significance Miscible in water Resultant protein do not require purification High yield • Problems Low tolerance by m/o High heat of fermentation Oxygen requirement is high.
History • Role of ICI in EU Used 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 tonnespruteen per anum • Costs of fermenter