Pollution to Product—a Novel Two-Stage Single-Pot Fermentative Production of 1,3-Propanediol

Abstract

Many industrial chemicals are currently produced from fossil resources. However, extensive use of fossil fuels has resulted in an alarming array of energy and pollution-related challenges. The industrial chemicals that are produced from fossil resources could be produced alternatively using green route in a sustainable manner. Here we report the production of 1,3-propanediol (1,3-PDO) through fermentative route using sugarcane processing wastes (sugarcane bagasse). This study used the second-generation (2G) fermentable sugar (2G FS) recovered from the low-cost feedstock sugarcane bagasse as a substrate for 1,3-PDO production through a mixed culture fermentation in a single pot using Saccharomyces cerevisiae NCIM 3594 and Klebsiella pneumoniae NCIM 2957. This novel concept of single-pot, mixed culture fermentation method to produce 1,3-PDO was verified by optimizing process parameters like substrate concentration (2G FS), pH, and temperature. The concentration of 2G FS was varied in the range of 0.5–5% (V_{2G FS}/V_{working volume}), pH was varied between 6 and 7, and the temperature range was 30–37°C. The maximum production of 1,3-PDO was observed at the concentration of 5% (V_{2G FS}/V_{working volume}), at an optimum pH of 6.8 and a temperature of 35°C. The evaluated thermodynamics parameters for analyzing the rate of fermentation were enthalpy (ΔH), ?47596 KJ/mol; activation energy (ΔE), ?47596 KJ/mol; entropy (ΔS), 500.46 J/mol; and Gibbs free energy (ΔG), ?2.018?×?10⁵?J/mol; and the kinetics parameters were specific growth rate (μ), 0.0053 h^?1; cell mass productivity (Q_x), 0.249 g/L^/h; rate of production (Q_p), 0.237 g/L^/h; and product yield (Y_p/s), 0.0427 g/g. This work demonstrates a novel single-pot method to produce 1,3-PDO from a low-cost feedstock and makes a valuable contribution to the development of a cost-effective fermentation based on renewable resources.