生物氧化产碱去除半纤维素水解物中的有机酸

盔形毕赤酵母Pichia galeiforms B-10对半纤维素水解物中的有机酸具有良好的降解活性,影响它脱酸活性的最主要因素是水解物初始pH。将半纤维素水解物初始pH值调节至5.0以上而无需其他处理,Pichia galeiforms B-10便可发挥良好的脱酸发酵性能。Pichia galeiforms B-10代谢有机酸盐可产生碱性物质,使水解液pH升高。在pH值5.0的条件下,只要调节补酸(补加低pH值水解物)的速率与代谢耗酸速率相平衡,发酵体系即可始终处于有利于酵母快速代谢有机酸的高pH环境。这种生物氧化产碱连续脱酸发酵方式,可有效降低中和半纤维素水解物的外加用碱量,具有降低成本,减少新污染物的优势。

Removal of Organic Acid from Hemicellulose Hydrolysate by Bio-oxidation to Produce Alkali

Pichia galeiforms B-10 has a good ability to degrade organic acid in hemicellulose hydrolysate, and this depickling activity of the strain is mainly affected by the initial pH value of hydrolysate. If the initial pH value of hemicellulose hydrolysate was adjusted above 5.0, Pichia galeiforms B-10 would exhibit an excellent capability of depickling fermentation without any other treatment. During the metabolism of organic acid salt by Pichia galeiforms B-10, alkali products were generated and this caused the raising of pH value. Therefore, under the condition of pH > 5.0, if only the acid supplying speed (by adding hydrolysate with low pH value) was adjusted to be in balance with the acid metabolizing speed, the fermentation system would always be kept in a high pH circumstance which was advantageous to the metabolism of organic acid by yeast. This mode, by using bio?oxidation to produce alkali for the continuous depickling fermentation, effectively reduced the addition of alkali during the neutralization of hemicellulose hydrolysate, and finally lowered the processing cost and generated less pollutant.