Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, USA.
Nat Commun. 2022 Jul 5;13(1):3870. doi: 10.1038/s41467-022-31433-x.
Economically viable production of cellulosic biofuels requires operation at high solids loadings-on the order of 15 wt%. To this end we characterize Nature's ability to deconstruct and utilize mid-season switchgrass at increasing solid loadings using an anaerobic methanogenic microbiome. This community exhibits undiminished fractional carbohydrate solubilization at loadings ranging from 30 g/L to 150 g/L. Metaproteomic interrogation reveals marked increases in the abundance of specific carbohydrate-active enzyme classes. Significant enrichment of auxiliary activity family 6 enzymes at higher solids suggests a role for Fenton chemistry. Stress-response proteins accompanying these reactions are similarly upregulated at higher solids, as are β-glucosidases, xylosidases, carbohydrate-debranching, and pectin-acting enzymes-all of which indicate that removal of deconstruction inhibitors is important for observed undiminished solubilization. Our work provides insights into the mechanisms by which natural microbiomes effectively deconstruct and utilize lignocellulose at high solids loadings, informing the future development of defined cultures for efficient bioconversion.
经济可行的纤维素生物燃料生产需要在高固体负荷下运行——约 15wt%。为此，我们使用厌氧产甲烷微生物组来描述自然界在增加固体负荷时解构和利用中期柳枝稷的能力。该群落显示出在 30g/L 至 150g/L 的负荷范围内，碳水化合物的分数溶解率没有降低。代谢蛋白质组学的研究揭示了特定碳水化合物活性酶类的丰度显著增加。在较高的固体含量下，辅助活性家族 6 酶的显著富集表明芬顿化学的作用。伴随着这些反应的应激反应蛋白在较高的固体含量下也被上调，β-葡萄糖苷酶、木糖苷酶、碳水化合物分支酶和果胶作用酶也是如此——所有这些都表明，去除解构抑制剂对于观察到的溶解率没有降低是很重要的。我们的工作为天然微生物组在高固体负荷下有效解构和利用木质纤维素的机制提供了深入了解，为高效生物转化的定义培养物的未来发展提供了信息。
