戊酸对地中海盐杆菌生产食品废物中聚羟基烷酸酯的影响。
Effect of levulinic acid on production of polyhydroxyalkanoates from food waste by Haloferax mediterranei.
机构信息
School of Energy and Environment, City University of Hong Kong, Tat Chee Ave, Kowloon, Hong Kong.
Technology Development Centre, Council of Scientific and Industrial Research-National Environmental Engineering Research Institute (CSIR - NEERI), Nehru Marg, Nagpur, 440020, Maharashtra, India.
出版信息
Environ Res. 2022 Nov;214(Pt 3):114001. doi: 10.1016/j.envres.2022.114001. Epub 2022 Aug 5.
Polyhydroxyalkanoates (PHA), especially poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is considered as the most suitable candidate to replace petrochemical plastics. However, the high production cost and the composition of the monomers in the copolymer are the major constraints in production. The 3-hydroxyvalerate (3HV) rich copolymers are ideal for various applications due to their lower melting points, improved elasticity, and ductility. Haloferax mediterranei is a suitable microorganism for the production of biopolymer PHBV from biowaste. Nevertheless, the potential of H. mediterranei cultivated on food waste as sustainable substrate and levulinic acid as an inducer has not been explored for PHBV production. This study aims at the valorization of food waste as low-cost substrate and evaluation of effect of levulinic acid in the production and composition of PHBV using H. mediterranei. Shake-flask fermentations using different concentrations of salt, glucose and levulinic acid were first performed to optimize the cultivation conditions. The highest growth of the halophile was observed at salt concentration of 15% and glucose of concentration 10 g/L. Under optimized growth conditions, H. mediterranei was cultivated for PHBV production in fed-batch bioreactor with pulse fed levulinic acid. The maximum biomass of 3.19 ± 0.66 g/L was achieved after 140 h of cultivation with 3 g/L of levulinic acid. A decrease in H. mediterranei growth was noticed with the increase in levulinic acid concentration in the range of 3-10 g/L. The overall yield of PHBV at 3, 5, 7 and 10 g/L of levulinic acid were 18.23%, 56.70%, 31.54%, 21.29%, respectively. The optimum concentration of 5 g/L of levulinic acid was found to produce the maximum yield of 56.70% PHBV with 18.55 mol% 3HV content. A correlation between levulinic acid concentrations and PHBV production established in this study can serve as an important reference for future large-scale production.
聚羟基脂肪酸酯（PHA），特别是聚（3-羟基丁酸酯-co-3-羟基戊酸酯）（PHBV）被认为是最适合替代石油基塑料的材料。然而，其高生产成本和共聚物中单体的组成是生产的主要限制因素。由于其较低的熔点、改善的弹性和延展性，3-羟基戊酸（3HV）丰富的共聚物更适用于各种应用。盐单胞菌属地中海是一种从生物废物中生产生物聚合物 PHBV 的合适微生物。然而，利用食物废物作为可持续基质和利用乙酰丙酸作为诱导物培养 H. mediterranei 生产 PHBV 的潜力尚未得到探索。本研究旨在利用食物废物作为低成本基质，并评估乙酰丙酸对 H. mediterranei 生产 PHBV 的产量和组成的影响。首先使用不同浓度的盐、葡萄糖和乙酰丙酸进行摇瓶发酵，以优化培养条件。在盐浓度为 15%和葡萄糖浓度为 10 g/L 的条件下，嗜盐菌的生长最高。在优化的生长条件下，用脉冲进料乙酰丙酸在分批式生物反应器中培养 H. mediterranei 生产 PHBV。在培养 140 小时后，用 3 g/L 的乙酰丙酸实现了 3.19±0.66 g/L 的最大生物量。当乙酰丙酸浓度在 3-10 g/L 范围内增加时，H. mediterranei 的生长会减少。在 3、5、7 和 10 g/L 的乙酰丙酸浓度下，PHBV 的总收率分别为 18.23%、56.70%、31.54%和 21.29%。发现 5 g/L 的乙酰丙酸浓度是产生最大 56.70% PHBV 产量的最佳浓度，其 3HV 含量为 18.55 mol%。本研究建立的乙酰丙酸浓度与 PHBV 产量之间的相关性可为未来的大规模生产提供重要参考。
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