Bioconversion and deodorization of shrimp processing waste by Xerocomus badius and inhibitory activity of converted product on angiotensin I-converting enzyme

Shrimp processing waste were converted by Xerocomus badius, bioconversion conditions and then optimized through Plackett-Burman design, path of steepest ascent and response surface methodology in order to recycle the solid waste efficiently. Based on the results of Plackett-Burman design and path of steepest ascent, a central composite design was applied for the regression models of the highest mycelium biomass and ACE inhibitory rate of water extract from the mycelium. The optimal cultural conditions for the highest mycelium biomass and ACE inhibitory rate were determined to be: A solid to liquid ratio of 12.421, 7.964% of content of bran powder and 1.117% of glacial acetic acid. Fermenting with the optimal cultural conditions resulted in an mycelium biomass of 28.890 g L^-1 and ACE inhibitory rate of water extract (0.400 g mL^-1) of 69.746% (IC₅₀ = 0.212 mg mL^-1). These values are consistent with the values predicted by the corresponding regression models (RSD<5%) and improved by 38.210 and 38.948%, respectively compared to that gained before optimization. The yield of ACE inhibitory water extract reached to 13.926 g L^-1 and was improved by 44.596%. Besides, bioconversio, Xerocomus badius has effective deodorization effect. This study improved that it is practicable and efficient to recycle the shrimp processing waste with bioconversion by Xerocomus badius and afforded an experimental and theoretical foundation for low-cost reusing shrimp processing waste and producing ACE inhibitor in industrial scale.