A novel strategy of gifting antibacterial activity to the waste from food processing: Probiotic fermentation combining with enzymatic hydrolysis of rice wine residue

This study proposed a strategy combining enzymatic hydrolysis and probiotic fermentation for sustainable utilization of the residue from the processing of Chongming Baijiu, a kind of traditional glutinous rice wine in China. The residue is featured with abundant hydrophobic amino acids content, thereby taken advantage for the production of antimicrobial peptides (AMPs). After the comparison of the hydrolysis with pepsin and alkaline protease, the hydrolysate of alkaline protease with higher hydrolysis degree and more plenty of peptides less than 1 kDa was chosen as the substance for the further fermentation by Lactiplantibacillus plantarum X7022 possessing 84 types of peptidases or proteases among its genome. The product (RRPHF) can effectively inhibit the growth of Staphylococcus aureus by penetrating the biofilm, and then inhibiting the cell survivability as well as damaging the cellular integrity. There are 646 peptides identified from the RRPHF through Nano HPLC MS/MS, with 75 pieces of high-scoring AMPs predicted. Moreover, enzyme cleavage site analysis and peptide molecular weight determination confirmed that the peptidases or proteases of L. plantarum X7022 could effectively produce AMPs rich in hydrophobic amino acids.

The results demonstrated that combining enzymatic hydrolysis with probiotic fermentation is a prospect approach for the AMPs yielding, offering a feasibly substantial pathway for the high-value application of by-product in food industry.