Applied Biochemistry and Biotechnology ( IF 3.1 ) Pub Date : 2021-01-23 , DOI: 10.1007/s12010-021-03503-1 Mine Güngörmüşler 1, 2 , Ali Tamayol 1, 3 , David B Levin 1
|
Biological hydrogen (H2) is a promising candidate for production of renewable hydrogen. Using entrapped cells rather than conventional suspended cell cultures for the production of H2 offers several advantages, such as improved production yields related to higher cell density, and enhanced resistance to substrate and end-product inhibition. In this study, H2 production by a novel isolate of Clostridium intestinale (strain URNW) was evaluated using cells entrapped within 2% calcium-alginate beads under strictly anaerobic conditions. Both immobilized cells and suspended cultures were studied in sequential batch-mode anaerobic fermentation over 192 h. The production of H2 in the headspace was examined for four different initial cellobiose concentrations (5, 10, 20, and 40 mM). Although a lag period for initiation of the fermentation process was observed for bacteria entrapped within hydrogel beads, the immobilized cells achieved both higher volumetric production rates (mmol H2/(L culture h)) and molar yields (mol H2/mol glucose equivalent) of H2 compared with suspended cultures. In the current study, the maximum cellobiose consumption rate of 0.40 mM/h, corresponding to 133.3 mg/(L h), was achieved after 72 h of fermentation by immobilized cells, generating a high hydrogen yield of 3.57 mol H2/mol cellobiose, whereas suspended cultures only yielded 1.77 mol H2/mol cellobiose. The results suggest that cells remain viable within the hydrogels and proliferated with a slow rate over the course of fermentation. The stable productivity of immobilized cells over 8 days with four changes of medium depicted that the immobilized cells of the isolated strain can successfully yield higher hydrogen and lower soluble metabolites than suspended cells suggesting a feasible process for future applications for bioH2 production.
Graphical abstract
中文翻译：
使用藻酸盐珠通过肠梭状芽孢杆菌菌株 URNW 的固定化细胞产氢
生物氢（H 2）是生产可再生氢的有希望的候选者。使用包埋的细胞而不是传统的悬浮细胞培养物来生产 H 2 有几个优点，例如与更高的细胞密度相关的产量提高，以及对底物和终产物抑制的抵抗力增强。在这项研究中，在严格厌氧条件下，使用包裹在 2% 海藻酸钙珠中的细胞评估了一种新型肠梭菌分离物（菌株 URNW）的H 2产量。在连续分批模式厌氧发酵中研究了固定细胞和悬浮培养物超过 192 小时。H 2 的产生检查顶部空间中四种不同的初始纤维二糖浓度（5、10、20 和 40 mM）。尽管观察到包埋在水凝胶珠中的细菌在发酵过程开始时存在滞后期，但固定化细胞实现了更高的体积生产率（mmol H 2 /（L 培养 h））和摩尔产量（mol H 2 /mol 葡萄糖当量） ) 的 H 2与悬浮培养物相比。在目前的研究中，固定化细胞发酵 72 小时后，最大纤维二糖消耗率为 0.40 mM/h，相当于 133.3 mg/(L h)，产生的氢气产量高达 3.57 mol H 2 /mol 纤维二糖, 而悬浮培养仅产生 1.77 mol H 2/mol 纤维二糖。结果表明，细胞在水凝胶内保持活力，并在发酵过程中以缓慢的速度增殖。固定化细胞在 8 天内的稳定生产力和四次培养基的变化表明，与悬浮细胞相比，分离菌株的固定化细胞可以成功地产生更高的氢和更低的可溶性代谢物，这表明未来 bioH 2生产应用的可行方法。
京公网安备 11010802027423号