Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznan, Poland.
Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland.
Environ Sci Technol. 2020 May 5;54(9):5864-5873. doi: 10.1021/acs.est.9b07651. Epub 2020 Apr 22.
Chain elongation is a process that produces medium chain fatty acids such as caproic acid, which is one of the promising products of the carboxylate platform. This study analyzed the impact of bioaugmentation of heat-treated anaerobic digester sludge with (AS + Ck) on caproic acid production from a mixed substrate (lactose, lactate, acetate, and ethanol). It was compared with processes initiated with non-augmented heat-treated anaerobic digester sludge (AS) and mono-culture of (Ck). Moreover, stability of the chain elongation process was evaluated by performing repeated batch experiments. All bacterial cultures demonstrated efficient caproate production in the first batch cycle. After 18 days, caproate concentration reached 9.06 ± 0.43, 7.86 ± 0.38, and 7.67 ± 0.37 g/L for AS, Ck, and AS + Ck cultures, respectively. In the second cycle, AS microbiome was enriched toward caproate production and showed the highest caproate concentration of 11.44 ± 0.47 g/L. On the other hand, bioaugmented culture showed the lowest caproate production in the second cycle (4.10 ± 0.30 g/L). Microbiome analysis in both AS and AS + Ck culture samples indicated strong enrichment toward the anaerobic order of Clostridia. Strains belonging to genera , , , and were dominating in the bioreactors.
链延长是一种产生中链脂肪酸的过程，例如己酸，它是羧酸化合物平台的有前途的产物之一。本研究分析了用 （AS + Ck）对热处理厌氧消化污泥进行生物增强对混合基质（乳糖、乳酸盐、醋酸盐和乙醇）生产己酸的影响。它与用未增强的热处理厌氧消化污泥（AS）和 （Ck）单培养物启动的过程进行了比较。此外，通过进行重复批处理实验评估了链延长过程的稳定性。所有细菌培养物在第一个批处理循环中都表现出高效的己酸生产能力。18 天后，AS、Ck 和 AS + Ck 培养物中的己酸浓度分别达到 9.06 ± 0.43、7.86 ± 0.38 和 7.67 ± 0.37 g/L。在第二个循环中，AS 微生物组对己酸生产进行了富集，并显示出最高的己酸浓度 11.44 ± 0.47 g/L。另一方面，生物增强培养物在第二个循环中表现出最低的己酸产量（4.10 ± 0.30 g/L）。AS 和 AS + Ck 培养物样品中的微生物组分析表明，对严格厌氧菌纲的强烈富集。属于属 、 、 、 和 的菌株在生物反应器中占主导地位。
