The article describes the construction of bacterial strains and plasmids for the production of a novel bioelectric device for converting microbial fermentation products into electricity. The authors constructed strains of E. coli using genetic engineering to express specific enzymes that break down xylan, a type of hemicellulose, into α-ketoglutarate, a valuable precursor for various compounds. They also constructed plasmids to express these enzymes on the surface of bacterial cells or inside the cells.
The authors created these plasmids by PCR (Polymerase Chain Reaction) and subcloning using the pET-28a vector. They then transformed these plasmids into E. coli cells and verified their expression using various enzymes.
The authors also developed a bioanode and biocathode for the microbial fuel cell, with the bioanode containing modified carbon cloth (CC) with MWCNTs (Multi-Walled Carbon Nanotubes) and the biocathode containing E. coli-laccase. They tested the performance of the microbial fuel cell with the anodic substrate xylan from corncob, and found that it can produce α-ketoglutarate and electricity stably for a long time.
The study also used scanning electron microscopy to observe the morphology of the bio-nanocomposite modified CC, verifying the attachment of E. coli consortia and MWCNTs to the surface.
The authors used various analytical methods to detect the concentrations of D-xylose, L-arabinose, and α-ketoglutarate using HPLC (High-Pressure Liquid Chromatography). They performed cyclic voltammetry (CV) at 37°C to test the electrochemical reactions and obtained statistically significant results.