Degradation of chitin and antagonism in Phomopsis asparagi by Bacillus amyloliquefaciens MY001北大核心CSCD

About 10 billion tons of chitin, a natural polymer, is generated annually. However, the utilization of chitin was hindered because of the lack of a clean and effective degradation process. In this study, bacterial strains with chitosanase-producing ability were isolated from soil and identified using 16S rDNA, gyrA, and gyrB gene sequence analysis. In addition, the degradation of insoluble chitin and antifungal capability of the bacterial strains were investigated. One selected isolate was identified as Bacillus amyloliquefaciens strain MY001. It showed antagonistic effect on Phomopsis asparagi (Sacc.) Bubak and could degrade insoluble chitin. The combination of chitin/chitosan and MY001 strain could enhance the inhibition on the growth of P. asparagi. In conclusion, strain B. amyloliquefaciens MY001 can directly degrade chitin. The combination of MY001 strain with chitin shows more effective inhibition on P. asparagi growth. These results suggest the direct utilization of chitin against fungal diseases of crops. © 2018 Science Press. All rights reserved.     

利用栗褐芽孢杆菌除藻的试验研究

应用筛选出的溶藻细菌--栗褐芽孢杆菌(Bacillus badius)进行除藻试验,结果表明该溶藻菌种除藻效果显著,对藻类的去除率在70%以上,对氨氮和有机物也有较好的去除效果;栗褐芽孢杆菌通过其分泌的一种特殊物质灭活藻类.     

微生物絮凝剂对高浓度重金属离子废水絮凝作用研究

文章研究了胶质芽孢杆菌(Bacillus mucilaginosus)产生的微生物絮凝剂(MBF)对高浓度重金属离子模拟废水的絮凝作用。采用的方法是将10mLMBF分别加入到100mL含Fe3+、Al3+、Pb2+、Zn2+、Ca2+和Mg2+的模拟废水中,分析MBF对不同重金属离子(浓度范围100~1000mg/L)模拟废水的絮凝作用。结果表明,不同重金属离子模拟废水经MBF处理后,出现明显不同的絮凝现象;随着废水重金属离子浓度增大,絮凝处理效率降低;废水经MBF处理后pH值比原水pH值下降。研究结果为进一步研究微生物絮凝剂处理含重金属离子废水提供参考资料。     

Isolation of Cr(Ⅵ) reducing bacteria from industrial effluents and their potential use in bioremediation of chromium containing wastewater

The present study is aimed at assessing the ability of Bacillus sp.JDM-2-1 and Staphylococcus capitis to reduce hexavalent chromium into its trivalent form.Bacillus sp.JDM-2-1 could tolerate Cr(Ⅵ) (4800 μg/mL) and S.capitis could tolerate Cr(Ⅵ) (2800 μg/mL).Both organisms were able to resist Cd2+ (50 μg/mL),Cu2+ (200 μg/mL),Pb2+ (800 μg/mL),Hg2+ (50 μg/mL) and Ni2+ (4000 μg/mL).S.capitis resisted Zn2+ at 700 μg/mL while Bacillus sp.JDM-2-1 only showed resistance up to 50 μg/mL.Bacillus sp.JDM-2-1 and S.capitis showed optimum growth at pH 6 and 7,respectively,while both bacteria showed optimum growth at 37℃.Bacillus sp.JDM-2-1 and S.capitis could reduce 85% and 81% of hexavalent chromium from the medium after 96 h and were also capable of reducing hexavalent chromium 86% and 89%,respectively,from the industrial effluents after 144 h.Cell free extracts of Bacillus sp.JDM-2-1 and S.capitis showed reduction of 83% and 70% at concentration of 10 μg Cr(Ⅵ)/mL,respectively.The presence of an induced protein having molecular weight around 25 kDa in the presence of chromium points out a possible role of this protein in chromium reduction.The bacterial isolates can be exploited for bioremediation of hexavalent chromium containing wastes,since they seem to have the potential to reduce the toxic hexavalent form to its nontoxic trivalent form.     

一株芽孢杆菌及其破乳特性研究

从某油污样品中分离、筛选出一株破乳菌株10#,经鉴定属芽孢杆菌属。该菌株对油田稳定O/W乳化液具明显的破乳效果。该菌株最佳培养条件为:温度30~35℃,pH7.0~7.5,生长时间48~72h,碳源为液体石蜡。该菌株在培养48h后具有明显而稳定的破乳效果,破乳活性部位为菌体。     

耐盐好氧反硝化菌筛选及其反硝化特性的研究

为了筛选耐盐好氧反硝化菌,对活性污泥进行耐盐与好氧反硝化驯化后,分离得到具有很强反硝化能力的菌株GQ-42,经菌落形态特征观察、生理生化测定及16S rDNA测序及同源性比较等过程,鉴定为蜡状芽孢杆菌.通过对菌株GQ-42进行反硝化特性的研究,确定适宜的反硝化条件为:碳氮比≥6,温度26～38℃,pH6.0～9.0,溶...     

甲基对硫磷降解菌的分离鉴定及降解特性研究

从湖北仙桃农药厂附近长期受农药污染的土壤中分离出1株甲基对硫磷降解菌HS-MP12,该菌能利用甲基对硫磷(MP)和对硝基苯酚(PNP)作为唯一的碳源、氮源生长.在24 h内,HS-MP12对起始质量浓度为500 mg/L和200 mg/L的MP降解率分别为86.8%和95.7%,对起始质量浓度为200 mg/L的PNP的降解率为92.3%,测定条件为: pH值6,温度30 ℃.HS-MP12经过形态观察、生理生化鉴定、16S rDNA序列测定和同源性分析,初步鉴定HS-MP12菌株为蜡状芽孢杆菌( Bacillus cereus).实验结果表明, HS-MP12在降解MP时,没有代谢中间产物对硝基苯酚的积累,推测可能存在不同的降解途径.     

Isolation and algae-lysing characteristics of the algicidal bacterium B5

Water blooms have become a worldwide environmental problem.Recently,algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms.In this study,one strain of algicidal bacterium B5 was isolated from activated sludge.On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence,it was identified as Bacillusfusiformis.Its algae- lysing characteristics on Microcystis aeruginosa,Chlorella and Scenedesmus were tested.The results showed that:(1)the algicidal bacterium B5 is a Gram-negative bacterium.The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B.fusiformis reached 99.86%,so B5 was identified as B.fusiformis;(2)the algal-lysing effects of the algicidal bacterium B5 on M.aeruginosa, Chlorella and Scenedesmus were pronounced.The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-α.The greater the initial bacterial cell density,the faster the degradation of chlorophyll-α.The greater the initial algal cell density,the slower the degradation of chlorophyll-α.When the bacterial cell density was 3.6 x l07 cells/ml,nearly 90% of chlorophyll-αwas removed.When the chlorophyll-αconcentration was less than 550μg/L,about 70% was removed;(3)the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.     

一株蜡状芽孢杆菌降解毒死蜱的影响因素研究

为了明确一株蜡状芽孢杆菌(Bacillus cereus HY-2)对毒死蜱的降解特性,在基础培养基中定量添加毒死蜱和降解菌进行混合摇培,每12 h取样检测毒死蜱残留量和菌株生长量,研究了接种量、毒死蜱初始质量浓度和含盐量等因素对菌株降解毒死蜱的影响。结果表明,接种量为8%(体积分数,接种体密度为OD600=3.0)时对80mg/L毒死蜱的降解率最高,为53%。随毒死蜱初始质量浓度增加,菌株的生长受到不同程度的抑制,然而随着毒死蜱的降解,菌体的生长量迅速增加,培养液的p H值随降解菌的增殖而逐渐上升。毒死蜱初始质量浓度为40~150 mg/L时,随降解时间延长,毒死蜱的残留质量浓度逐渐下降;而毒死蜱初始质量浓度为200 mg/L时,毒死蜱质量浓度在降解过程中出现了先上升后下降、然后逐渐下降的现象。降解菌对Na Cl有较高的耐受度,当Na Cl质量浓度为20~70 g/L时,降解菌在60 h时对80 mg/L毒死蜱的降解率为27%~53%。     

味精工业高浓度有机废水培养苏云金芽孢杆菌的研究

利用味精工业发酵废水进行了培养苏云金芽孢杆菌（Bacillus thuringiensis,Bt）以生产生物农药的实验研究.经过对废水成分分析和预处理、Bt菌种驯化、摇瓶机发酵配方正交优化实验和生物毒性测定,探讨了一条经济可行的工艺路线.该工艺在利用发酵废水生产生物农药时不会产生二次污染问题,具有较高的工业应用价值,对于其他发酵工业废水的资源化处理也有一定参考价值.