State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Environ Sci Technol. 2022 Jun 21;56(12):8702-8711. doi: 10.1021/acs.est.1c07894. Epub 2022 May 13.
During proteinaceous waste valorization to produce volatile fatty acids (VFAs), protein needs to be hydrolyzed to amino acids (AAs), but the effects of the configuration of AAs on their biotransformation and VFA production have not been investigated. In this study, more residual d-AAs than their corresponding l-AAs were observed after VFAs were produced from kitchen waste in a pilot-scale bioreactor. For all AAs investigated, the VFA production from d-AAs was lower than that from corresponding l-AAs. The metagenomics and metaproteomics analyses revealed that the l-AA fermentation system exhibited greater bacterial chemotaxis and quorum sensing (QS) than d-AAs, which benefited the establishment of functional microorganisms (such as , , and ) and expression of functional proteins (e.g., substrate transportation cofactors, l-AA dehydrogenase, and acidogenic proteins). In addition, d-AAs need to be racemized to l-AAs before being metabolized, and the difference of VFA production between d-AAs and l-AAs decreased with the increase of racemization activity. The findings of the AA configuration affecting bacterial chemotaxis and QS, which altered microorganism communities and functional protein expression, provided a new insight into the reasons for higher l-AA metabolism than d-AAs and more d-AAs left during VFA production from proteinaceous wastes.
在将蛋白质废物转化为挥发性脂肪酸 (VFAs) 以生产有用物质的过程中，蛋白质需要先水解为氨基酸 (AAs)，但 AAs 构型对其生物转化和 VFA 生成的影响尚未得到研究。在这项研究中，在一个中试规模的生物反应器中，利用厨房垃圾生产 VFAs 后，发现残留的 d-AAs 比相应的 l-AAs 多。在所研究的所有 AAs 中，d-AAs 生成 VFA 的能力均低于相应的 l-AAs。宏基因组学和宏蛋白质组学分析表明，l-AA 发酵系统的细菌趋化性和群体感应 (QS) 比 d-AAs 更强，这有利于功能微生物（如、和）的建立和功能蛋白（如底物运输辅因子、l-AA 脱氢酶和产酸蛋白）的表达。此外，d-AAs 在代谢之前需要消旋化为 l-AAs，d-AAs 和 l-AAs 之间的 VFA 生成差异随着消旋化活性的增加而减小。AA 构型影响细菌趋化性和 QS 的发现改变了微生物群落和功能蛋白的表达，为 l-AA 代谢率高于 d-AAs 以及在从蛋白质废物生产 VFA 过程中留下更多 d-AAs 提供了新的见解。
