Department of Chemistry and Chemical Engineering, Beijing Forestry University, Beijing, China.
BMC Biotechnol. 2014 Mar 20;14:21. doi: 10.1186/1472-6750-14-21.
Enhancement of enzymatic digestibility by some supplementations could reduce enzyme loading and cost, which is still too high to realize economical production of lignocellulosic biofuels. A recent study indicates that yeast hydrolysates (YH) have improved the efficiency of cellulases on digestibility of furfural residues (FR). In the current work, the components of YH were separated by centrifugation and size exclusion chromatography and finally characterized in order to better understand this positive effect.
A 60.8% of nitrogen of yeast cells was remained in the slurry (YHS) after hydrothermal treatment. In the supernatant of YH (YHL), substances of high molecular weight were identified as proteins and other UV-absorbing compounds, which showed close molecular weight to components of cellulases. Those substances attributed to a synergetic positive effect on enzymatic hydrolysis of FR. The fraction of YHL ranged from 1.19 to 2.19 mL (elution volume) contained over 50% of proteins in YHL and had the best performance in stimulating the release of glucose. Experiment results proved the adsorption of proteins in YHL on lignin.
Supplementation of cellulases with YH enhances enzymatic digestibility of FR mainly by a competitive adsorption of non-enzymatic substances on lignin. The molecular weight of these substances has a significant impact on their performance. Different strategies can be used for a good utilization of yeast cells in terms of biorefinery concept.
通过某些补充物来提高酶的消化率可以减少酶的用量和成本，而这仍然太高，无法实现木质纤维素生物燃料的经济生产。最近的一项研究表明，酵母水解物（YH）提高了纤维素酶对糠醛残基（FR）消化效率。在目前的工作中，通过离心和分子筛层析将 YH 的成分进行了分离，并对其进行了最终的特性鉴定，以便更好地理解这种积极的影响。
酵母细胞的 60.8%的氮在水热处理后的浆（YHS）中得以保留。在 YH 的上清液（YHL）中，发现了高分子量的物质，被鉴定为蛋白质和其他具有紫外吸收的化合物，它们与纤维素酶的成分分子量相近。这些物质对 FR 的酶解具有协同的积极作用。YHL 的洗脱体积为 1.19 至 2.19 毫升的部分，含有 YHL 中超过 50%的蛋白质，在刺激葡萄糖释放方面表现最佳。实验结果证明了 YHL 中的蛋白质在木质素上的吸附。
用 YH 补充纤维素酶主要通过非酶物质对木质素的竞争吸附来增强 FR 的酶解消化性。这些物质的分子量对其性能有显著影响。根据生物炼制概念，可以采用不同的策略来充分利用酵母细胞。
