Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química e Bioloxía (CICA), BIOENGIN Group, University of A Coruña, E-15008-A Coruña, Spain.
Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent 9000, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat, Ghent 9052, Belgium.
Bioresour Technol. 2024 Sep;408:131138. doi: 10.1016/j.biortech.2024.131138. Epub 2024 Jul 21.
Recently, there has been notable interest in researching and industrially producing medium-chain carboxylic acids (MCCAs) like n-caproate and n-caprylate via chain elongation process. This study presents a comprehensive assessment of the behavior and MCCA production profiles of Clostridium kluyveri in batch and continuous modes, at different ethanol:acetate molar ratios (1.5:1, 3.5:1 and 5.5:1). The highest n-caproate concentration, 12.9 ± 0.67 g/L (92.9 ± 1.39 % MCCA selectivity), was achieved in batch mode at a 3.5:1 ratio. Interestingly, higher ratios favored batch mode selectivity over continuous mode when this was equal or higher to 3.5:1. Steady state operation yielded the highest n-caproate (9.5 ± 0.13 g/L) and n-caprylate (0.35 ± 0.020 g/L) concentrations at the 3.5:1 ratio. Increased ethanol:acetate ratios led to a higher excessive ethanol oxidation (EEO) in both operational modes, potentially limiting n-caproate production and selectivity, especially at the 5.5:1 ratio. Overall, this study reports the efficient MCCA production of both batch and continuous modes by C. kluyveri.
最近，人们对通过链延伸工艺研究和工业生产中链羧酸（MCCAs）如己酸和辛酸产生了浓厚的兴趣。本研究全面评估了在不同乙醇：乙酸摩尔比（1.5:1、3.5:1 和 5.5:1）下，在分批和连续模式下，凝结芽孢杆菌的行为和 MCCAs 生产曲线。在 3.5:1 的比例下，分批模式下达到了最高的己酸浓度 12.9±0.67g/L（92.9±1.39%MCCA 选择性）。有趣的是，当比值等于或高于 3.5:1 时，较高的比值有利于分批模式的选择性，而不是连续模式。在 3.5:1 的比例下，稳态操作得到了最高的己酸（9.5±0.13g/L）和辛酸（0.35±0.020g/L）浓度。在两种操作模式下，增加乙醇：乙酸的比例导致更高的过量乙醇氧化（EEO），可能限制己酸的生产和选择性，特别是在 5.5:1 的比例下。总的来说，本研究报道了凝结芽孢杆菌通过分批和连续模式高效生产 MCCAs。
