Production of Single Cell Protein from the Wastes of Cynodon dactylon L. Using Mixed Culture of Bacillus cereus and Fusarium solani

Abstract

Single cell protein (SCP) is known to be the total protein extracted from microbial cultures. In the present study, SCP was produced from the wastes of Cynodon dactylon L. using a mixed culture of Bacillus cereus and filamentous fungus Fusarium solani. The results revealed that best productivity was at pH of 7.5 using 0.5/100 mL of inoculum size (52 x 10⁸ cell/mL bacterial cells and 10⁵ conidia/mL of the fungus). The incubation time and temperature were investigated; 8 days of incubation at 30 °C were the best conditions for the production of SCP. The highest productivity of SCP as a dry weight was at the level of 4% of carbon source, and the SCP production reached a maximum level 81.5 g/L. Protein 28%, carbohydrate 17%, lipid 2.46%, ash 31.66%, phosphorus 42 mg/L, sodium 29 mg/L, potassium 35 mg/L, DNA 2%, and RNA 1.64% were determined in the SCP. In the toxicity assay, no aflatoxin was detected in the produced SCP, and the percentage of Ochratoxin and T-2 Toxin was 10.6 and 122.9 ppm respectively. The total concentration of amino acids in the SCP was 84.74 mg/100 mL, and it contained the followings: Lysine, Leucine, Cysteine, Methionine, Phenylalanine, Tyrosine, Valine, and Threonine. This work suggests that mixed culture can be used for production of SCP. Additionally, analysis of the produced SCP indicated that it has nutritional value, and thus it can exploit in the animal feed and possibly, as a substrate for energy generation.