Microbial phosphine production: The key to improve productivity

Abstract

Abstract This study focused on the metabolic pathways of Pseudescherichia sp. SFM4 phosphine production. Phosphine originated from biochemical stage of functional bacteria synthesize pyruvate in the cycle of tricarboxylic acid (TCA). Stirring the aggregated bacterial mass could lead to the increase in the yield of phosphine by 40%. Furthermore, the additional supply of pure hydrogen directly could lead to the increase in phosphine production by 44%. When inhibiting functional bacteria to produce hydrogen, the concentration of phosphine was significantly reduced. Microbial aggregates were observed after 12 hours, and phosphine was detected at this time. Extracellular polymeric substances (EPS) secreted on microbial aggregates was primarily attributed to the functional groups responsible for the synthesis of phosphine-related substances. Compared with the control with only bacteria addition (60 mg/m3 PH3), the concentration of phosphine in the treatment with mixture of EPS and bacteria was increased to 100 mg/m3 after 48 h. The relative expressions of phoN and phoD related to phosphatase synthesis were up-regulated in functional bacteria during the phosphine production. It was implied that the phosphine produced by functional bacteria was derived from the decomposition of intracellular organophosphorus with C-P bonds by phosphatase.