Degradation of gossypol and improvement of nutritional components in defatted cottonseed meal through fermentation by a synthetic microbial community.

Certain microbes can enhance the utilization and nutritional value of defatted cottonseed meal, an oilseed processing by-product. In this study, 11 microbial strains with strong gossypol-degrading activity were identified. The interactions among these 11 gossypol-resistant strains were examined using supernatant cross-feeding assays. Based on these interactions, 28 synthetic microbial communities (SynComs) were constructed. Evaluation of the fermentation performance of these SynComs revealed four core functional strains of YZ-1 (Pichia kudriavzevii LNTJQ-1), YZ-3 (Wickerhamomyces anomalus YJQ-1), YZ-6 (Candida tropicalis TJQ-4), and YZ-7 (Saccharomyces cerevisiae LNTJQ-3). Among the tested SynComs, SC5 (composed of YZ-1, YZ-3, and YZ-7) was identified as the optimal consortium. SC5 degraded free gossypol by 93.82 % (Reducing from 1068.00 mg/kg to 66.00 mg/kg), while increasing crude protein content by 11.08 % and total amino acid content by 7.98 % based on dry matter. In summary, the screening of gossypol degradation microbes and construction of SynComs improved the nutritional value and utilization of defatted cottonseed meal, providing a feasible solution for developing defatted cottonseed meal as an animal feed resource.