Screening and Identification of the Strain Pediococcus acidilactici and Its Application in Fermentation of Corn-Soybean Meal Uncooked Materials

Cost and contamination are the bottleneck problems for the replacement of antibiotics with fermented feed. A strain of lactic acid bacteria was isolated and screened from acidified apple juice and identified as Pediococcus acidilactici using morphological, physiological, and biochemical tests and 16S rDNA sequence analysis. The strain was combined with Bacillus subtilis and Saccharomyces cerevisiae to ferment raw corn-soybean meal, and the two-stage fermentation process was optimized with a single-factor test, orthogonal test, and response surface methodology. Compared with unfermented raw material, the protein content of fermented feed was increased by 5.21 percentage points (p < 0.05) and the total amino acids were increased by 3.7 percentage points (p < 0.05), making it rich in amino acids essential for pigs. The high-throughput sequencing results showed that, at the species level, the highest relative abundances of bacteria in the fermentation system were those of Pediococcus acidilactici and Bacillus subtilis, and the most abundant fungi was Saccharomyces cerevisiae. No pathogenic bacteria, such as Salmonella, were detected in the fermentation system. This paper provides a feasible scheme for cheap preparation of an alternative to antibiotics, fermented feed, with uncooked raw materials. It has positive significance for promoting high-value utilization of agricultural and sideline products and improving feed cost-effectiveness.

Automated summary

A strain of lactic acid bacteria, Pediococcus acidilactici, was isolated and combined with Bacillus subtilis and Saccharomyces cerevisiae to ferment raw corn-soybean meal. Through optimization, the fermented feed showed increased protein content and total amino acids, which is beneficial for pig growth.