Transcript single cell protein - EngineeringDuniya.com

SINGLE CELL PROTEIN
• A protein extracted from cultured algae,
yeasts or bacteria
• Used as a substitute for protein-rich foods.
1. Spirulina
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A free-floating filamentous cyanobacterium
Photosynthetic organism
Arthrospira maxima
Arthrospira platensis
Grown in open ponds or basins.
Production of Spirulina
3 major steps:
• Cultivation of alga in constructed ponds.
– Constant agitation of water using paddle
wheels
– To keep nutrients evenly dispersed
– To expose all the cells to sunlight.
• Harvest of algal biomass using filters to
recover biomass.
• Washed biomass is dried & pulverized;
Package
Uses of Spirulina
• Against anemia, diabetes
• For healing of wounds & lowering of
cholesterol.
• As a protein supplement in
– human diets
– feeds for livestock – poultry, cattle, pig
– aquaculture
– sericulture
• Food colourant
• Contains unusually high amounts of
protein: 55-77% by dry weight, depending
upon the source
• Contains all essential amino acids
• Met, Cys & Lys are quite lesser.
• Contains Vitamins B1, B2, B3, B6, B9,
B12, C, D & E.
• Rich source of K
• Also has Ca, Cr, Cu, Fe, Mg, Mn, P, Se,
Na and Zn.
• Contains many photosynthetic pigments
2. Scytalidium acidophilum
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Acid-Tolerant Fungus
Bioconversion of waste paper to SCP
pH < 1
Waste paper pretreated with 72% H2SO4 at 4°C
Adequate sugar-containing substrate for fungal
growth
• Glucose, galactose, mannose, xylose, arabinose
in the hydrolysates
• Converted to cell biomass
• 44 to 47% crude protein were obtained
• SCP from microbial cultivation has a
higher proportion of nucleic acids
• Human beings lack the enzyme uricase,
unlike animals.
• So, unable to convert uric acid, derived
from nucleic acids to allantoin.
• Thus, if SCP is for human consumption, a
prior reduction in its nucleic acid content is
done.
• For the separation and recovery of nucleic
acids
– Fragmentation of the cells using a wet
crushing mill
– Extraction with hot salt solutions
– Minimizes protein solubility, while, being good
solvents for nucleic acids.
3. SCP from Cassava
• Cassava as a substrate for SCP
• Filamentous fungi, on ground cassava
roots
– Supplemented with NH4Cl & CSL
– Biomass containing 13-24% crude protein.
• Aspergillus fumigatus
– Fermented whole cassava in continuous
fermentation system
– Product containing 37% crude proteins.
• Rhodopseudomonas gelatinosa
– A photosynthetic bacterium
– Cultivated on cassava starch medium
• The yeast, Candida utilis
– Fermented enzymatically (α-amylase)
hydrolyzed cassava in a submerged culture
– Product contains 35% crude protein
– Commercially used.
4. SCP from ram horn hydrolysate
• Ram horns hydrolyzed by treating with acid (6N–
HCl)
• Ram horn hydrolysate (RHH) obtained
• Hydrolysate used as substrate to grow Bacillus
cereus, Bacillus subtilis and Escherichia coli in
batch system at 30 °C with stirring 150 rpm
• Rich in total protein
• 66%, 68% & 71% for E. coli, B. cereus and B.
subtilis
• Protein produced, contains all essential amino
acids for ruminant feed.
• SCP, produced by 2 types of fermentation
processes…
• Submerged fermentation
– Substrate always in a liquid which contains
the nutrient needed for growth.
– Substrate is held in fermentor, operated
continuously
– Product biomass is continuously harvested.
– Product is filtered or centrifuged and then
dried.
– More capital intensive & higher operating cost
• Advantages of SCP over conventional
protein sources are:
– Independent of land and climate;
– Works on a continuous basis
– Can be genetically controlled
– Causes less pollution.
• Factors that impair the usefulness of SCP:
– Non-digestible cell wall (mainly algae)
– High nucleic acid content
– Unacceptable coloration (mainly with algae)
– Disagreeable flavour (in algae & yeasts)
SINGLE CELL OIL
1. Yarrowia lipolytica
• Grown in a continuous mode
• Produces ~ 10g dry biomass per L
• Contains 0.25 g oil per g dry weight
biomass
• If an aqueous extract from Teucrium
polium was added, oil content increased to
~ 0.40
2. Mortierella isabellina
• Remarkable cell growth upto ~36 g/L
• High fat quantities accumulated inside
fungal mycelia: 50–55%, wt/wt oil in dry
biomass
• Notable SCO production of ~18 g/L of
culture medium.
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3. Cryptococcus curvatus
• An oleaginous yeast grown on batch mode
on diluted (25%) prickly-pear juice.
• Biomass upto 11 g/L
• Accumulated 46% (w/w) lipid
• Extracted lipids were mainly oleic (18:1)
and palmitic (16:0) acids
4. Candida curvata & Trichosporon cutaneum
• Yeasts
• Cheese whey used as media for producing
oil and SCP
• 6.3 to 9.3 g of oil/liter of whey
• Fat contains oleic (~50%), palmitic
(~30%), stearic (~15%) & linoleic (~8%)
acids.
• SCP, rich in Met & other essential amino
acids.