Efficient 1,3-Propanediol production from lignocellulosic hydrolysate via g-C3N4-L. Reuteri lighting-driven biohybrid system

A light-responsive biohybrid system was constructed by coupling graphitic carbon nitride (g-C₃N₄) with Lactobacillus reuteri to enhance 1,3-propanediol (1,3-PDO) biosynthesis. Under simulated sunlight, the g-C₃N₄/L. reuteri biohybrid system achieved a 1,3-PDO titer of 11.3 g/L within 48 h in synthesis medium, representing a 66 % increase compared to dark controls (6.8 g/L). Characterization results confirmed strong interfacial coupling and efficient electron transfer between the photocatalyst and microbial cells. Notably, the light-driven biohybrid system increased the intracellular NADH/NAD⁺ ratio and ATP levels by 98.3 % and 378.5 %, respectively, highlighting its ability to regulate redox balance and promote energy metabolism. Furthermore, the hybrid system was further applied using enzymatic hydrolysate of glycerol-pretreated hemp straw as the sole carbon source, replacing the synthesis medium. Impressively, the illuminated biohybrid system still achieved a 1,3-PDO titer of 9.6 g/L, significantly outperforming the non-illuminated control (5.9 g/L). Overall, this study demonstrates the feasibility of using g-C₃N₄-assisted biohybrid systems to enhance microbial bioconversion, especially with enzymatic lignocellulosic hydrolysates, offering a sustainable route for value-added chemical production by integrating biomass and solar energy.