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浙江大学学报（农业与生命科学版）
浙江大学学报(农业与生命科学版)  2012, Vol. 38 Issue (6): 669-674    DOI: 10.3785/j.issn.1008-9209.2012.01.041
生物科学与技术     
  巨大芽孢杆菌MBFF6产絮凝剂培养条件的优化及絮凝剂的化学性质
  曹芳，余秀梅，郭娟利，杨晓尧，潘康成*  
四川农业大学 动物医学院 动物疫病与人类健康四川省重点实验室，四川 雅安 625014
Optimization of culture conditions for bioflocculant-producing Bacillus megaterium MBFF6 and its chemical characteristics
CAO Fang, YU Xiu-mei, GUO Juan-li, YANG Xiao-yao, PAN Kang-cheng*
Sichuan Province Key Laboratory of Animal Disease & Human Health, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan 625014, China
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摘要： 采用单因子试验，分别考察培养时间、碳源、氮源、碳氮浓度比、pH值、金属离子、培养温度和接种量对巨大芽孢杆菌MBFF6产絮凝剂的影响，同时对絮凝剂的热稳定性和化学性质进行研究. 结果表明：巨大芽孢杆菌MBFF6产絮凝剂的最佳培养基组成为葡萄糖5 g/L，(NH4)2SO4 0.5 g/L，K2HPO4 5 g/L，KH2PO4 2 g/L，MgSO4·7H2O 0.2 g/L，初始pH 7；最佳培养条件为φ(接种量) = 2 %，温度30 °C，转速150 r/min，时间24 h；该絮凝剂具有良好的热稳定性；经化学反应分析，定性的判断出该絮凝剂的有效成分是多糖和蛋白质；经红外光谱分析，该絮凝剂分子结构中有羟基、氨基、羰基和甲氧基. 表明该絮凝剂产生菌MBFF6具有营养要求简单、发酵周期短和絮凝活性高的优点，是一株很有应用前景的絮凝剂产生菌.
Abstract:   At present, flocculants are prevalent in the variety of industrial processes such as wastewater treatment, drinking water purification and downstream processing in fermentation processes. In general, flocculants are classified into three groups: inorganic flocculants, organic synthetic flocculants and naturally occurring flocculants. Bioflocculants have received considerable scientific and biotechnological attention in recent years because of their biodegradability, harmlessness and lack of secondary pollution of their degradation intermediates. Compared with inorganic flocculants and synthetic flocculants, bioflocculants have not yet been produced industrially because of their low flocculating capability and high cost. In order to reduce costs of production, research is needed to Bacillus megaterium MBFF6, and the strain producing bioflocculant B. megaterium MBFF6 was investigated by signal factor test. At the same time, thermal stability and chemical characteristics of bioflocculant were studied. The bioflocculant BF6 was purified from supernatant by ethanol precipitation. Whether containing α-amino acids and polysaccharide of the purified bioflocculant was analyzed by ninhydrin reaction and Molish and anthrone reaction. Proteins and nucleic acids were qualitatively determined by UV spectrophotometry. The chemical groups of purified bioflocculant were analyzed using a Fourier-transform infrared (FTIR) spectrophotometer (FTIR-8400S). was named as BF6. In this study, Optimization for culture conditions of strain MBFF6 and chemical characteristics of bioflocculant BF6 were studied. The effect of culture time, carbon source, nitrogen source, C/N ratio, pH, metal ions, culture temperature and inoculum size on bioflocculant production byidentify and select new bioflocculant-producing microorganisms and strains capable of utilizing low-cost substrates, and to learn how to optimize fermentation conditions to enhance bioflocculant activity. We had previously screened a bioflocculant-producing strain identified as The results indicated that the optimal medium for bioflocculant production was glucose 5 g/L, (NH4)2SO4 0.5 g/L, K2HPO4 5 g/L, KH2PO4 2 g/L, MgSO4·7H2O 0.2 g/L, pH 7; The optimal culture conditions were inoculum size 2 % (V/V), culture temperature 30 °C, and shaking speed 150 r/min for 24 h (Fig. 1-5). This bioflocculant was stable at 60-100 °C. The production of bioflocculant BF6 from fermentation broth was 1.28 g/L and it was a white powdery substance. The results of color reaction showed that the anthrone reaction produced blue-green compounds, and Molish reaction appeared a clear violet ring on the boundary of sulfuric acid and samples, and the ninhydrin reaction produced blue compounds, which indicated that the bioflocculant contained polysaccharide and protein. The results of UV spectrophotometry revealed that there was a faint characteristic absorption peak at 280 nm, but no absorption peak at 260 nm, confirming that the bioflocculant was primarily consisted of polysaccharide and proteins but no nucleic acids. Infrared spectrophotometry analysis revealed that this bioflocculant contained hydroxyl, amino, carbonyl, and methoxyl groups in its structure and these groups were the preferred ones for flocculation process (Fig. 6). The experimental result above shows that the bioflocculant-producing strain MBFF6 has such advantages as simple nutrition and short fermentation period, and it synthesises a bioflocculant with better thermal stability and high flocculating activity. It can be seen that the B. megaterium MBFF6 is a very broad application bioflocculant-producing strain. Bioflocculant BF6 may find possible application as a polymer for environmental bioremediation and other biotechnological processes. Further studies on its flocculation mechanism and scaling-up culture process are in progress in order to enhance the bioflocculant production and realize its industrial and agricultural utilization.
出版日期: 2012-11-20
基金资助:

“教育部长江学者和创新团队发展计划”创新团队资助项目 (IRT0848).
通讯作者: 潘康成，E-mail: pankangcheng71@126.com   
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曹芳
余秀梅
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杨晓尧
潘康成

引用本文:

曹芳，余秀梅，郭娟利，杨晓尧，潘康成.   巨大芽孢杆菌MBFF6产絮凝剂培养条件的优化及絮凝剂的化学性质[J]. 浙江大学学报(农业与生命科学版), 2012, 38(6): 669-674.

CAO Fang, YU Xiu-mei, GUO Juan-li, YANG Xiao-yao, PAN Kang-cheng*. Optimization of culture conditions for bioflocculant-producing Bacillus megaterium MBFF6 and its chemical characteristics. , 2012, 38(6): 669-674.

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http://www.zjujournals.com/agr/CN/10.3785/j.issn.1008-9209.2012.01.041    或    http://www.zjujournals.com/agr/CN/Y2012/V38/I6/669

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