Resource utilization of penicillin fermentation fungi residue for ectoine production by Halomonas elongata

Penicillin fermentation fungal residue (PFFR), a hazardous waste with over 90 % organic matter, can pollute the environment if not properly disposed of. In this study, acid/alkaline heat pretreatment was employed to remove antibiotic residues and break down macromolecular compounds into smaller molecules. The hydrolysate contained 17.23 g/L of total amino acids, 5.34 g/L of reducing sugars, and 33.6 g/L of salts. PFFR hydrolysate was then used as the base medium for the halophile Halomonas elongata to produce the high-value compound ectoine. Response surface methodology was used to optimize medium conditions, resulting in a maximum ectoine concentration of 3957.06 ± 214.12 mg/L. Additionally, a cost-effective mixture of corn steep liquor and hydrolysate was employed for fed-batch cultivation, combined with gradient salt shock to optimize fermentation. The final ectoine yield reached 15837.02 ± 422.27 mg/L. This study offers a cost-effective, environmentally friendly, and efficient strategy for the resource utilization of PFFR.