Isopropanol production using engineered Corynebacterium glutamicum from waste rice straw biomass.

Isopropanol, a well-known biofuel, is a widely used precursor for chemical products that can replace nonrenewable petroleum energy. Here, engineered Corynebacterium glutamicum that can effectively utilize all xylose and glucose in agricultural waste rice straw to produce isopropanol was described. First, codon mutations were introduced into transporters and glycolytic-related genes to decrease the glucose preference of C. glutamicum. A more energetically favorable xylose oxidative pathway was constructed that replaced traditional xylose isomerization pathways, saving twice the number of enzymatic steps. A succinate auxiliary module was incorporated into the tricarboxylic acid cycle (TCA), connecting the xylose-utilized pathway with the isopropanol pathway to maximize xylose orientation towards the product. The final engineered strain successfully consumed 100 % of the xylose from NaOH-pretreated, enzyme-hydrolyzed rice straw and effectively synthesized 4.91 g/L isopropanol. This study showcases the successful conversion of agricultural waste into renewable energy, unveiling new possibilities for advancing biological fermentation technology.

Recent advances in microbial production of medium chain fatty acid from renewable carbon resources: A comprehensive review.

Microbial production of medium chain length fatty acids (MCFAs) from renewable resources is becoming increasingly important in establishing a sustainable and clean chemical industry. This review comprehensively summarizes current advances in microbial MCFA production from renewable resources. Detailed information is provided on two major MCFA production pathways using various renewable resources and other auxiliary pathways supporting MCFA production to help understand the fundamentals of bio-based MCFA production. In addition, conventional and well-studied MCFA producers are classified into two categories, natural and synthetic producers, and their characteristics on MCFA production are outlined. Moreover, various engineering strategies employed to achieve the highest MCFAs production up to date are showcased together with key enzymes suggested for MCFA overproduction. Finally, future challenges and perspectives are discussed towards more efficient production of bio-based MCFA production.