Enhanced biohydrogen production from the dark co-fermentation of tequila vinasse and nixtamalization wastewater: Novel insights into ecological regulation by pH
Enhanced biohydrogen production from the dark co-fermentation of tequila vinasse and nixtamalization wastewater: Novel insights into ecological regulation by pH
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DOI：
10.1016/j.fuel.2019.04.147
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发表时间：
2019-10-01
期刊：
影响因子：
7.4
通讯作者：
Leon-Becerril, Elizabeth
中科院分区：
文献类型：
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作者：
Garcia-Depraect, Octavio;Rene, Eldon R.;Leon-Becerril, Elizabeth
本研究的主要目的是通过混合培养研究pH对80%龙舌兰酒糟和20%蒸煮废水（w/w）暗共发酵生产乳酸盐和乙酸盐基bioH（2）的影响。在5.8和6.5的恒定pH值下操作3-L充分混合的分批反应器，在所有情况下精确度为+/-0.05 pH单位。无论pH值如何，bioH（2）的产生主要来自乳酸的消耗。在产生的bioH 2的量方面没有观察到显著差异，即2133 NmL/L-反应器，最大速率为155 NmL/L-h。与pH 5.8相比，pH 6.5缩短了滞后时间，但通过丙酸盐形成促进bioH（2）下沉。在此基础上，提出了两阶段pH控制策略，即第一阶段pH为6.5，第二阶段pH为5.8，以避免发酵时间过长和产丙酸。pH改变策略减少了操作时间，并将bioH（2）产量提高了17%。此外，该策略还促进了梭菌和乳酸菌之间的互养，抑制了布劳特氏菌和丙酸杆菌的增殖，使bioH（2）的产生趋向于提高效率。总的来说，微生物动力学表明，从乳酸盐和乙酸盐成功生产bioH（2）依赖于乳酸盐和乙酸盐的生产者和消费者之间的最佳微生物平衡，这被发现是pH依赖性的。
The main aim of this work was to study the effect of pH on lactate-and acetate-based bioH(2) production from the dark co-fermentation of 80% tequila vinasse and 20% nixtamalization wastewater (w/w) by mixed culture. A 3-L well-mixed batch reactor was operated at constant pH values of 5.8 and 6.5, with an accuracy of +/- 0.05 pH units in all the cases. Regardless of pH, bioH(2) production derived mostly from the consumption of lactate. No significant differences were observed in the amount of bioH2 produced, i.e. 2133 NmL/L-reactor with a maximum rate of 155 NmL/L-h. Compared to a pH of 5.8, pH 6.5 shortened the lag time but promoted bioH(2) sink through propionate formation. Based on the above results, a two-stage controlled-pH strategy was proposed by maintaining the first stage at pH 6.5 and the second stage at pH 5.8 for avoiding long fermentation time and propionogenesis, respectively. The pH-shift strategy reduced the operational time and enhanced bioH(2) production by 17%. Besides, this strategy also stimulated the syntrophy between Clostridium and Lactobacillus, and reduced the proliferation of Blautia and Propionibacterium, trending bioH(2) production to enhanced efficiency. Overall, microbial dynamics showed that successful bioH(2) production from lactate and acetate relies on having an optimum microbial equilibrium between producers and consumers of lactate and acetate, which was found to be pH-dependent.