Improved engineered fungal-bacterial commensal consortia simultaneously degrade multiantibiotics and biotransform food waste into lipopeptides

Resource utilization of food waste is necessary to reduce environmental pollution. However, antibiotics can enter the environment through food waste, resulting in antibiotic residues, which pose potential risks to human health. In this study, commensal artificial consortia were constructed through intercellular adaptation to simultaneously degrade antibiotics and bioconvert food waste into lipopeptides. The biodegradation efficiency of oxytetracycline in the three-strain consortium, which contained lipopeptide-producing Bacillus amyloliquefaciens HM618, high-level proline-producing Corynebacterium glutamate, and laccase-producing Pichia pastoris, was around 100% in the food waste medium at 72 h; this was higher than that in the pure culture of P. pastoris-Lac. Sulfamethoxazole could be removed at 48 h. However, the lipopeptide level in the three-strain consortium was only 77 mg/L. The four-strain consortium containing free fatty acid-producing Yarrowia lipolytica improved the lipopeptide level to around 218 mg/L. The degradation efficiency of oxytetracycline in the four-strain consortium was 100% at 48 h; however, only 56% of the sulfamethoxazole was removed over 96 h. Three five-strain consortia were formed by introducing recombinant manganese peroxidase-producing P. pastoris, recombinant HM618 with high-level amylase, and serine-producing C. glutamicum. In low starch food waste, the highest degradation efficiency of sulfamethoxazole was 71%, while oxytetracycline could be completely removed at 48 h. However, oxytetracycline inhibited starch degradation and lipopeptide production. The high level of starch improved lipopeptide synthesis to 1280 mg/L. The results of this study provide a feasible strategy for the resource utilization of inferior biomass food waste.