Mixed fermentation of Chlorella pyrenoidosa and Bacillus velezensis SW-37 by optimization

Abstract

In this study, the fermentation of Chlorella pyrenoidosa (C. pyrenoidosa) with a series of probiotics was investigated using optimization to enhance good flavor and remove deodorization from the high-yield protein Chlorella. Bacillus velezensis SW-37 was screened for their deodorizing and proteolytic activity on C. pyrenoidosa. The ideal fermentation conditions were determined as pH value of 9.30, liquid-to-material ratio of 8.80 mL/g, inoculum concentration of 10%, fermentation time of 24 h, and temperature of 37 °C. Under the optimized conditions, the protein extraction rate of C. pyrenoidosa reached 61.20%, and the hydrolysis rate of the protein reached 56.96%. Compared to unfermented C. pyrenoidosa (unFC), the number of volatiles was reduced from 30 to 24. In addition, aromatic substances such as isophorone, 3-methyl-p-anisaldehyde, and fumaric acid were produced to improve the flavor of fermented C. pyrenoidosa (FC) products. This study provided an effective fermentation method for improving the flavor of Chlorella and obtaining high-yield protein, which was expected to contribute to the development of Chlorella protein in various fields of the food industry.