Biofuel and Biocatalysis Innovation Research Unit, Nakhonsawan Campus, Mahidol University, Nakhonsawan, 60130, Thailand.
Bio4gas (Thailand) Company Limited, Phatthalung, 93210, Thailand.
Curr Microbiol. 2024 Jun 27;81(8):244. doi: 10.1007/s00284-024-03780-z.
A novel thermotolerant caproic acid-producing bacterial strain, Clostridium M1NH, was successfully isolated from sewage sludge. Ethanol and acetic acid at a molar ratio of 4:1 proved to be the optimal substrates, yielding a maximum caproic acid production of 3.5 g/L. Clostridium M1NH exhibited remarkable tolerance to high concentrations of ethanol (up to 5% v/v), acetic acid (up to 5% w/v), and caproic acid (up to 2% w/v). The strain also demonstrated a wide pH tolerance range (pH 5.5-7.5) and an elevated temperature optimum between 35 and 40 °C. Phylogenetic analysis based on 16S rRNA gene sequences revealed that Clostridium M1NH shares a 98% similarity with Clostridium luticellarii DSM 29923. The robustness of strain M1NH and its efficient caproic acid production from low-cost substrates highlight its potential for sustainable bio-based chemical production. The maximum caproic acid yield achieved by Clostridium M1NH was 1.6-fold higher than that reported for C. kluyveri under similar fermentation conditions. This study opens new avenues for valorizing waste streams and advancing a circular economy model in the chemical industry.
从污水污泥中成功分离出一株新型耐温己酸产生菌，名为 Clostridium M1NH。研究发现，乙醇和乙酸的摩尔比为 4:1 时为最佳底物，己酸的最大产量可达 3.5 g/L。Clostridium M1NH 对高浓度乙醇（高达 5% v/v）、乙酸（高达 5% w/v）和己酸（高达 2% w/v）表现出显著的耐受性。该菌株还表现出较宽的 pH 耐受范围（pH 5.5-7.5）和在 35-40°C 之间升高的最佳温度。基于 16S rRNA 基因序列的系统发育分析表明，Clostridium M1NH 与 Clostridium luticellarii DSM 29923 的相似度为 98%。菌株 M1NH 的稳健性及其从低成本底物高效生产己酸的能力突出了其在可持续生物基化学品生产中的潜力。Clostridium M1NH 的最大己酸产率比类似发酵条件下 C. kluyveri 的报道高出 1.6 倍。本研究为废物利用和推进化学工业循环经济模式开辟了新途径。
