Optimization of culture conditions of screened Galactomyces candidum for the production of single cell protein from biogas slurry

Abstract

Background: The use of single cell protein (SCP) has become a method for alleviating the shortage of protein feed that microorganisms propagate in a suitable culture medium. In this study, SCP was produced by yeast to use the nutrition contained in the biogas slurry of chicken manure. Results: The results showed that Galactomyces candidum was the most efficient at producing SCP among the seven yeasts studied. The maximum cell dry weight (CDW) 6.79 g/L and protein content 39.39%, were obtained under the fermentation conditions of initial NH4+-N concentration of 2000 mg/L and a C/N ratio of 6:1 with acetate as the pH regulator. The total CDW increased to 9.24 g/L after secondary fermentation. Metal elements had a little effect on the growth of G. candidum. The addition of sulfur not only promoted the synthesis of sulfur-containing amino acid cysteine but also increased protein content by promoting the synthesis of glutamic acid and glutamine. Conclusions: Future experiments should focus more on achieving high-density cultivation and more efficient utilization of ammonia nitrogen in the biogas slurry.How to cite: Zhou Pan, Zhang Lu, Ding Hongxia, et al. Optimization of culture conditions of screened Galactomyces candidum for the production of single cell protein from biogas slurry. Electron J Biotechnol 2021;55. https://doi.org/10.1016/j.ejbt.2021.11.006

Keywords

• Ammonia nitrogen
• Biogas
• Carbon-nitrogen ratios
• Chicken manure
• Galactomyces candidum
• Metal elements