Optimization of Specific Productivity for Xylonic Acid Production by Gluconobacter oxydans Using Response Surface Methodology.

Tao He,Chaozhong Xu,Xiaoli Gu,Xu Liu,Chenrong Ding

doi:10.3389/fbioe.2021.729988

Abstract

Large amounts of xylose cannot be efficiently metabolized and fermented due to strain limitations in lignocellulosic biorefinery. The conversion of xylose into high value chemicals can help to reduce the cost of commercialization. Therefore, xylonic acid with potential value in the construction industry offers a valuable alternative for xylose biorefinery. However, low productivity is the main challenge for xylonic acid fermentation. This study investigated the effect of three reaction parameters (agitation, aeration, and biomass concentration) on xylose acid production and optimized the key process parameters using response surface methodology The second order polynomial model was able to fit the experimental data by using multiple regression analysis. The maximum specific productivity was achieved with a value of 6.64 ± 0.20 g gx −1 h−1 at the optimal process parameters (agitation speed 728 rpm, aeration rate 7 L min−1, and biomass concentration 1.11 g L−1). These results may help to improve the production efficiency during xylose acid biotransformation from xylose.

Highlights

Xylose, which constitutes about 25% of the total biomass components, is unable to be converted in the lignocellulosic biorefinery process due to the limitation of microorganisms (Zaldivar et al, 2001)
The RSM examined the effect of three variables: agitation (A), aeration (B) and biomass concentration (C) on PX
The maximum PX for xylonic acid production was successfully obtained by multivariate optimization such as agitation, aeration and biomass concentration

Summary

Introduction

Xylose, which constitutes about 25% of the total biomass components, is unable to be converted in the lignocellulosic biorefinery process due to the limitation of microorganisms (Zaldivar et al, 2001). The utilization of xylose is one of the key factors affecting the commercial production of lignocellulose (Nogue and Karhumaa, 2015). Xylonic acid (XA), a bio-based chemical of great interest in recent years, is a non-toxic, nonvolatile, non-corrosive, water-soluble organic acid. This aldonic acid compound has a similar structure and properties to gluconic acid, and shows a wide variety of applications in various fields. XA has been used as a raw material for chelating agent, antibiotic, polyamide, hydrogel modifier and 1,2,4-butanetriol precursor (Gupta et al, 2001; Deppenmeier et al, 2002; Chun et al, 2006)

Methods

Results

Conclusion