In-situ sodium percarbonate assisting and intensifying the aerobic whole-cell catalysis and bio-oxidation of lignocellulosic xylose, glucose and glycerol

Abstract

Oxygen supply is one of the decisive factors of obligate aerobic microbial fermentation. Gluconobacter oxydans as a typical aerobic bacterium has excellent whole-cell catalysis and bio-oxidation ability to sugars and alcohols. By the dual function of oxygenation and alkali production of sodium percarbonate (SPC), the dissolved oxygen supply and pH stabilization was experimentally investigated and applied for the first time in G. oxydans fermentation. SPC performed a significant assisting effort to bio-oxidation performance by the in-situ oxygen supply and neutralization for whole-cell catalysis and bio-oxidation of lignocellulosic xylose, glucose, and glycerol. Compared with common aeration fermentation (and even the sealed pure-oxygen supplied mode), the bio-production of the three platform compounds xylonic acid, gluconic acid, and 1, 3-dihydroxyacetone was improved significantly by 45.7%, 28.4%, and 39.1%, respectively. In addition, the direct bioproduction of xylonic acid from the crude corncob sulfate hydrolysate was also improved by 17.3%. Within 4 h, 37.7 g/L of xylonic acid was produced in the fermentation tank, with a productivity of 9.4 g/L/h. The in-situ SPC assistance provides a simple and practical approach to intensify the bio-oxidation performance of G. oxydans for the whole-cell catalysis of high-value-added platform compounds from lignocellulosic feedstocks.