Biorefinery of Moldy Corn for Poly(3-hydroxybutyrate) Synthesis Utilizing Halomonas sp. DYZ-4: Unsterile Craft Model and Metabolic Mechanisms

Abstract

The elevated biomanufacturing costs, stemming from raw material expenditures and cumbersome processes, constrain the industrial application of poly(3-hydroxybutyrate) (PHB). Valorization of biowaste in an unsterile fermentation model represents a sustainable strategy. In this study, an excellent halophile was identified and utilized for converting moldy corn to synthesize PHB. The distinguished fermentation performance and comprehensive metabolic pathways of Halomonas sp. DYZ-4 were established. Subsequently, nutrient supply and physicochemical parameters were systematically tuned to strengthen PHB accumulation. The optimal biopolymer outputs in the conventional model and the open process were accordingly 6.81 and 6.83 g L–1; a straightforward production system was thus constructed. Furthermore, moldy corn pretreated with α-amylase yielded 10.72 g L–1 reducing sugar, which could serve as a novel generation feedstock for DYZ-4 proliferation. The maximum PHB concentration reached 6.83 g L–1 with a proportion of 61%, facilitating the resource conversion of waste. This study demonstrates Halomonas as a competitive non-sterilized platform to produce PHB, presenting a potential biomanufacturing scenario for the transformation of severely damaged agricultural debris.