College of Environmental Science and Engineering, State Environmental Protection Engineering Centre for Pollution Treatment and Control in Textile Industry, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.
College of Environmental Science and Engineering, State Environmental Protection Engineering Centre for Pollution Treatment and Control in Textile Industry, Donghua University, 2999 North Renmin Road, Shanghai 201620, China; Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, United States.
Bioresour Technol. 2020 Apr;302:122881. doi: 10.1016/j.biortech.2020.122881. Epub 2020 Jan 23.
In this study, a reliable approach using ammonia nitrogen was proposed to increase lactate production during semi-continuous food waste (FW) fermentation under mesophilic conditions. Both free ammonia nitrogen (FAN) and ammonium ion (NH-N) were present in mesophilic reactors, with a wide FAN/NH-N ratio variation due to the intermittent pH control. The investigation of responsible mechanisms revealed that the increased production yield of LA was associated with the acceleration of solubilization, hydrolysis, glycolysis and acidification. The presence of FAN and NH-N in proper concentrations increased lactate production by 2.4 folds and recovered lactate production to 24.5 g COD/L from low rate control reactor (9.6 g COD/L) under mesophilic conditions. Furthermore, the microorganisms responsible for LA accumulation (Bavariicoccus, Enterococcus, Bifidobacterium and Corynebacterium) were selectively enriched, and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways associated with carbohydrate transport and LA production were enhanced in nitrogen fed reactors.
本研究提出了一种在中温条件下利用氨氮提高半连续食物垃圾（FW）发酵过程中乳酸产量的可靠方法。在中温反应器中同时存在游离氨氮（FAN）和铵离子（NH-N），由于间歇 pH 控制，FAN/NH-N 比变化很大。对相关机制的研究表明，LA 产量增加与溶解、水解、糖酵解和酸化的加速有关。在适当浓度的 FAN 和 NH-N 存在下，LA 产量提高了 2.4 倍，在中温条件下，从低速率控制反应器（9.6 g COD/L）中恢复到 24.5 g COD/L。此外，选择性富集了负责 LA 积累的微生物（巴氏杆菌、肠球菌、双歧杆菌和棒状杆菌），并在氮供体反应器中增强了与碳水化合物运输和 LA 生产相关的 KEGG（京都基因与基因组百科全书）途径。
