Herein, an enhanced green production of xanthan gum has been achieved by utilizing orange peels. Response surface methodology and kinetic modeling were adapted for the process optimization and its influence on scale up production respectively. Optimal conditions for the maximum xanthan production were 1.62% acid hydrolysis, 85% carbon source of orange peel hydrolysate and 30.4 °C temperature. Furthermore, the optimized treatment was conducted in the batch culture fermentor to observe the associated variations during scale up process. In bio-fermentor, to the first time ever, xanthan production along with reducing sugar conversion and utilization rates reached 30.19 g/L, 69.29% and 99.99%, respectively. Employed characterization techniques of FTIR, XRD and HPLC confirmed the fermented product as xanthan gum and obtained an average molecular weight of 1.01 × 10 6 g/mol. This work on account of optimized process parameters presented maximum xanthan production from a waste material.
Xylanases with high specific activity has been focused with great interest as a useful enzyme in biomass utilization. The production of recombinant GH11 xylanase (MYCTH_56237) from Myceliophthora thermophila has been improved through N-terminal signal peptide engineering in P. pastoris. The production of newly recombinant xylanase (termed Mtxyn11C) was improved from 442.53 to 490.7 U/mL, through a replacement of α-factor signal peptide with the native xylanase signal peptide segment (MVSVKAVLLLGAAGTTLA) in P. pastoris. Scaling up of Mtxyn11C production in a 7.5 L fermentor was improved to the maximal production rate of 2503 U/mL. In this study, the degradation efficiency of Mtxyn11C was further examined. Analysis of the hydrolytic mode of action towards the birchwood xylan (BWX) revealed that Mtxyn11C was clearly more effective than commercial xylanase and degrades xylan into xylooligosaccharides (xylobiose, xylotriose, xylotetraose). More importantly, Mtxyn11C in combination with a single multifunctional xylanolytic enzyme, improved the hydrolysis of BWX into single xylose by 40%. Altogether, this study provided strategies for improved production of xylanase together with rapid conversion of xylose from BWX, which provides sustainable, cost-effective and environmental friendly approaches to produce xylose/XOSs for biomass energy or biofuels production.
危险品化学品经营许可证（带存储）