Enhancing erythritol production by wheat straw biochar-incorporated solid-state fermentation of agricultural wastes using defatted Schizochytrium sp. biomass as supplementary feedstock

Abstract Defatted Schizochytrium residue was used as a supplementary feedstock for efficiency erythritol production in this study. Microalgae are attractive feedstocks for the microbial process. However, proper enzymatic hydrolysis and toxicity alleviation must be considered for efficient fermentation. A strategy was proposed herein for producing erythritol from enzymatic hydrolysate of the defatted Schizochytrium residue (SRH), resorting to the wheat (Triticum aestivum L.) straw biochar-incorporated solid-state fermentation (SSF) of agricultural wastes to relieve the toxicant inhibition. Enhanced erythritol production (190.5 mg/gds) was achieved in batch SSF supplemented with 4% biochar and 20 % concentrated SRH, which was obtained from the cellulose–protease (1:1) system performed under pH 5.0 and 45 °C for 24 h with 0.8 % (m/v) of enzyme addition. Fed- and repeated-batch fermentation demonstrated enduring high cell viability and improved erythritol yield of 223.2 and 205.4 mg/gds, respectively. Cost analysis suggested high availabilities of raw substrates for erythritol cultivation, which was energy conserving and operable. Moreover, SRH was proven to be an economic alternative feedstock for low-cost erythritol production via the biochar-incorporated SSF.