Jin Tao, Käldström Mats, Benavides Adriana, Rechulski Marcelo D Kaufman, Jarboe Laura R
Department of Chemical and Biological Engineering, Iowa State University, 4134 Biorenewables Research Laboratory, 617 Bissell Rd, Ames, IA, USA.
Department of Heterogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Mulheim an der Ruhr, Germany.
AMB Express. 2020 Feb 3;10(1):28. doi: 10.1186/s13568-020-0965-4.
Mechanocatalysis is a promising method for depolymerization of lignocellulosic biomass. Microbial utilization of the resulting oligosaccharides is one potential route of adding value to the depolymerized biomass. However, it is unclear how readily these oligosaccharides are utilized by standard cell factories. Here, we investigate utilization of cellulose subjected to mechanocatalytic depolymerization, using ethanologenic Escherichia coli as a model fermentation organism. The mechanocatalytic oligosaccharides supported ethanol titers similar to those observed when glucose was provided at comparable concentrations. Tracking of the various oligomers, using maltose (alpha-1,4) and cellobiose (beta-1,4) oligomers as representative standards of the orientation, but not linkage, of the glycosidic bond, suggests that the malto-like-oligomers are more readily utilized than cello-like-oligomers, consistent with poor growth with cellotetraose or cellopentaose as sole carbon source. Thus, mechanocatalytic oligosaccharides are a promising substrate for cell factories, and microbial utilization of these sugars could possibly be improved by addressing utilization of cello-like oligomers.
机械催化是一种很有前景的木质纤维素生物质解聚方法。微生物利用所产生的低聚糖是提高解聚生物质附加值的一条潜在途径。然而，目前尚不清楚标准细胞工厂对这些低聚糖的利用程度如何。在此，我们以产乙醇的大肠杆菌作为模型发酵生物，研究了经机械催化解聚的纤维素的利用情况。机械催化产生的低聚糖所支持的乙醇滴度与提供相当浓度葡萄糖时所观察到的滴度相似。以麦芽糖（α-1,4）和纤维二糖（β-1,4）低聚糖作为糖苷键方向而非连接方式的代表性标准，对各种低聚物进行追踪，结果表明麦芽样低聚糖比纤维样低聚糖更易被利用，这与以纤维四糖或纤维五糖作为唯一碳源时生长较差的情况一致。因此，机械催化低聚糖是细胞工厂很有前景的底物，通过解决纤维样低聚糖的利用问题，可能会提高这些糖类的微生物利用率。
