Comparisons of Single Cell Protein Sources

The interesting part on this topic is Anupama and Ravindra (2000) had come out with a table to compare the SCP from algae, fungi and bacteria. The parameters used by them to evaluate the ranking of SCP showing that nucleic acid from algae is safer than fungi and bacteria. Nucleic acid from fungi is much better than bacteria due to their low nucleic acid contents.  Therefore the ranking will be algae > fungi > bacteria.

The comparison chart shows the composition of SCP from the respective organisms.

Component	Percentage composition of weight
	Algae	Fungi	Bacteria
True Protein	40-60a	30-70a	50-83a
Total nitrogen (Protein + nucleic acids)	45-65a	35-50a	60-80a
Lysin	4.6-7.0a	6.5-7.8a	4.3-5.8a
Methionine	1.4-2.6a	1.5-1.8a	2.2-3.0a
Fats/Lipids	5-10a	5-13a	8-10a
Carbohydrate	9	NA	NA
Bile pigments and Chlorophyll	6	NA	NA
Nucleic acids	4-6a	9.70	15-16a
Mineral acids	7	6.6	8.6
Amino acids	NA	54	65
Ash	3	NA	NA
Moisture	6.0	4.5-6.0a	2.8
Fiber	3	NA	NA

 ^a The yield varies with the type of substrate used, the specific organism used and the culture conditions maintained. NA - Not available

Sources : Brock, 1989; Frazier and Westhoff, 1990;  Powar and Daginawala, 1995; Ziino et al., 1999

Comparison of various parameters for SCP production from algae, fungi and bacteria

Parameter	Algae	Bacteria	Fungi (Yeast)	Fungi (Filamentous)
Growth Rate	Low	Highest	Quite High	Lower than bacteria and fungi
Substrate	Light, CO2	Wide  range	Wide range except CO2	Mostly lignocellulosic
pH range	upto 11	5-7	5-7	3-8
Cultivation	Ponds, bioreactors	Bioreactors	Bioreactors	Bioreactors
Contamination risks	High	Precautions needed	Low	Least if pH less than 5
S-containing amino acids	Low	Dificient	Dificient	Low
Nucleic acid removal	-	Required	Required	Required
Toxin	-	Endotoxin from gram –ve bacteria	-	Myotoxin in most species

Sources : Singh, 1998

References:

1. Anupama, Ravindra, P. 2000. Value-added food: Single cell protein. Biotechnology advances, 18., 459-479.

By:
R. Tevan