Palakawong Na Ayudthaya Susakul, van de Weijer Antonius H P, van Gelder Antonie H, Stams Alfons J M, de Vos Willem M, Plugge Caroline M
1Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
2Thailand Institute of Scientific and Technological Research, 35 Mu 3, Khlong Ha, Amphoe Khlong Luang, 12120 Pathum Thani Thailand.
Biotechnol Biofuels. 2018 Jan 25;11:13. doi: 10.1186/s13068-018-1012-4. eCollection 2018.
Exploring different microbial sources for biotechnological production of organic acids is important. Dutch and Thai cow rumen samples were used as inocula to produce organic acid from starch waste in anaerobic reactors. Organic acid production profiles were determined and microbial communities were compared using 16S ribosomal ribonucleic acid gene amplicon pyrosequencing.
In both reactors, lactate was the main initial product and was associated with growth of spp. (86% average relative abundance). Subsequently, lactate served as a substrate for secondary fermentations. In the reactor inoculated with rumen fluid from the Dutch cow, the relative abundance of and increased from the start, and lactate, acetate, formate and ethanol were produced. From day 1.33 to 2, lactate and acetate were degraded, resulting in butyrate production. Butyrate production coincided with a decrease in relative abundance of spp. and increased relative abundances of bacteria of other groups, including , , Helicobacteraceae, Peptostreptococcaceae and Porphyromonadaceae. In the reactor with the Thai cow inoculum, spp. also increased from the start. When lactate was consumed, acetate, propionate and butyrate were produced (day 3-4). After day 3, bacteria belonging to five dominant groups, _, , Enterobacteriaceae and Porphyromonadaceae, were detected and these showed significant positive correlations with acetate, propionate and butyrate levels.
The complexity of rumen microorganisms with high adaptation capacity makes rumen fluid a suitable source to convert organic waste into valuable products without the addition of hydrolytic enzymes. Starch waste is a source for organic acid production, especially lactate.
探索不同的微生物来源用于生物技术生产有机酸具有重要意义。荷兰和泰国奶牛瘤胃样本被用作接种物，以在厌氧反应器中从淀粉废料生产有机酸。测定了有机酸生产概况，并使用16S核糖体核糖核酸基因扩增子焦磷酸测序比较了微生物群落。
在两个反应器中，乳酸是主要的初始产物，并且与 spp. 的生长相关（平均相对丰度为86%）。随后，乳酸用作二次发酵的底物。在接种荷兰奶牛瘤胃液的反应器中， 和 的相对丰度从一开始就增加，并且产生了乳酸、乙酸、甲酸和乙醇。从第1.33天到第2天，乳酸和乙酸被降解，导致丁酸产生。丁酸的产生与 spp. 的相对丰度下降以及其他组细菌的相对丰度增加同时发生，包括 、 、螺杆菌科、消化链球菌科和卟啉单胞菌科。在接种泰国奶牛瘤胃液的反应器中， spp. 也从一开始就增加。当乳酸被消耗时，产生了乙酸、丙酸和丁酸（第3 - 4天）。第3天后，检测到属于五个优势组的细菌，即 、 、肠杆菌科和卟啉单胞菌科，并且这些细菌与乙酸、丙酸和丁酸水平显示出显著的正相关。
瘤胃微生物具有高度适应能力，其复杂性使得瘤胃液成为一种合适的来源，无需添加水解酶即可将有机废物转化为有价值的产品。淀粉废料是有机酸生产的来源，尤其是乳酸。
