pH对嗜盐混合菌发酵挥发性有机酸混合物合成PHA的影响
发布时间：2018-09-12 07:55
【摘要】：嗜盐混合菌发酵生产聚羟基脂肪酸酯(polyhydroxyalkanoate,PHA)具有免灭菌程序、产量高、易提取等优势而被广泛关注。集中考察了p H对嗜盐混合菌(MMCs)发酵混合挥发性有机酸(VFA)生产PHA的影响。研究结果表明,在6.5~8.2范围内p H对PHA合成没有明显影响,过高或者过低的p H都会降低PHA合成速率和VFA的吸收速率。发酵体系的p H影响了嗜盐MMC的PHA产量,但是在酸性和碱性条件下却存在不同的影响机制。碱性环境增大了VFA的解离程度,导致MMC对底物的吸收耗费大量的能量,造成VFA吸收速率的下降。这一作用在p H升高至9.2以上时表现显著。酸性环境下,分子态VFA进入细胞后改变了胞内的p H,降低了相关酶和蛋白质的活性,从而影响了底物的利用。当p H?5.2时微生物代谢及底物利用能耗量降低,导致PHA胞内降解利用率降低,刺激了PHA合成量的提高。PHA组分受p H影响不大,初始p H?5.2~10.2时羟基脂肪酸戊酯(hydroxyvalerate,HV)所占比例维持在34.9%~38.3%范围内。本研究对于进一步利用嗜盐MMC发酵含有混合VFA的废弃物生产PHA具有重要的指导意义。
[Abstract]:The production of polyhydroxyl fatty acid esters (polyhydroxyalkanoate,PHA) by mixed halophilic bacteria has been paid more and more attention because of its sterilizing procedure, high yield and easy extraction. The effect of pH on the production of PHA from mixed volatile organic acid (VFA) by halophilic mixed bacteria (MMCs) was investigated. The results showed that pH had no effect on the synthesis of PHA in the range of 6.5 ~ 8.2, and that high or low pH could decrease the synthesis rate of PHA and the absorption rate of VFA. The pH of fermentation system affected the PHA yield of halophilic MMC, but the mechanism was different under acidic and alkaline conditions. Alkaline environment increases the degree of VFA dissociation, which leads to the absorption of MMC to the substrate consuming a lot of energy, resulting in the decrease of VFA absorption rate. This effect was significant when pH increased to above 9.2. In acidic environment, molecular VFA changed the intracellular pH and decreased the activity of related enzymes and proteins, thus affecting the utilization of substrates. The energy consumption of microbial metabolism and substrate use decreased, which led to the decrease of intracellular degradation efficiency of PHA, and stimulated the increase of PHA synthesis. PHA component was not affected by pH. The proportion of initial pH 5.2 ~ 10.2 hydroxyl fatty acid amyl ester (hydroxyvalerate,HV) remained in the range of 34.9% and 38.3%. This study is of great significance for the further production of PHA from waste containing mixed VFA by halophilic MMC fermentation.
【作者单位】： 北京工业大学环境与能源工程学院;
【分类号】：X703
本文编号：2238387
[Abstract]:The production of polyhydroxyl fatty acid esters (polyhydroxyalkanoate,PHA) by mixed halophilic bacteria has been paid more and more attention because of its sterilizing procedure, high yield and easy extraction. The effect of pH on the production of PHA from mixed volatile organic acid (VFA) by halophilic mixed bacteria (MMCs) was investigated. The results showed that pH had no effect on the synthesis of PHA in the range of 6.5 ~ 8.2, and that high or low pH could decrease the synthesis rate of PHA and the absorption rate of VFA. The pH of fermentation system affected the PHA yield of halophilic MMC, but the mechanism was different under acidic and alkaline conditions. Alkaline environment increases the degree of VFA dissociation, which leads to the absorption of MMC to the substrate consuming a lot of energy, resulting in the decrease of VFA absorption rate. This effect was significant when pH increased to above 9.2. In acidic environment, molecular VFA changed the intracellular pH and decreased the activity of related enzymes and proteins, thus affecting the utilization of substrates. The energy consumption of microbial metabolism and substrate use decreased, which led to the decrease of intracellular degradation efficiency of PHA, and stimulated the increase of PHA synthesis. PHA component was not affected by pH. The proportion of initial pH 5.2 ~ 10.2 hydroxyl fatty acid amyl ester (hydroxyvalerate,HV) remained in the range of 34.9% and 38.3%. This study is of great significance for the further production of PHA from waste containing mixed VFA by halophilic MMC fermentation.
【作者单位】： 北京工业大学环境与能源工程学院;
【分类号】：X703
【相似文献】
相关会议论文 前5条
1 杨声莲;李登煜;郑林用;张小平;陈强;;混合菌在纤维素降解中的作用研究[A];四川省环境科学学会2003年学术年会论文集[C];2003年
2 李宗义;王海磊;王振宇;李培睿;;优势混合菌主要木质素降解酶的协同效应研究[A];微生物生态学研究进展——第五届微生物生态学术研讨会论文集[C];2003年
3 罗建中;刘鸿;康新宇;陈少红;刘玉红;齐水冰;操洲杏;;紫外诱变优势混合菌处理含氯废水的研究[A];中国环境保护产业发展战略论坛论文集[C];2000年
4 张燕玲;黄晓媛;陈振风;王福源;;混合菌处理泔脚pH值变化过程的研究[A];第一届全国化学工程与生物化工年会论文摘要集(下)[C];2004年
5 陈鹏宇;崔丽;张凯松;;混合菌生物污染的表面增强拉曼光谱研究[A];第十七届全国光散射学术会议摘要文集[C];2013年
相关硕士学位论文 前4条
1 陈界江;土著混合菌对表层沉积物中重金属形态、生物有效性的影响[D];吉林大学;2007年
2 周明;降解PVA混合菌系的环境影响因素及其降解机理的研究[D];西安工程大学;2011年
3 徐健全;固定化混合菌降解油烟废气的研究[D];浙江大学;2006年
4 李国强;两种木霉混合菌产酶的条件优化及其对玉米秸秆降解的研究[D];东北林业大学;2011年
，本文编号：2238387
本文链接：https://www.wllwen.com/kejilunwen/huanjinggongchenglunwen/2238387.html
最近更新
教材专著
