高效复合菌对多菌灵的生物降解

将多菌灵降解菌Alcaligenes sp.和Rhodococcua sp.(编号为A和R)按不同比例进行复配,并采用三波长校正法和HPLC法测定不同复配降解体系中多菌灵的残留量,比较了纯培养和复合菌群对多菌灵的降解效果,最后对高效复合菌的降解条件进行了优化.试验结果表明,得到的高效降解复合菌群AR5(A∶R复配比例1...     

滇池高效聚磷菌Rhodococcus sp.H的分离鉴定及除磷特性研究

采用混合稀释平板法,从富营养化湖泊底泥滇池中分离出1株高效聚磷菌,经分子生物学鉴定,推测其为红球菌属(Rhodococcus sp.),将其命名为Rhodococcus sp.H,并对菌株H在不同理化因素条件下的生长及除磷特性进行了研究。结果表明,该菌株在接种培养24 h后即能完成对数增长期,在pH值为6~7、温度为30℃时能获得较高生物量和除磷率,最佳碳源为乙酸钠和乙醇,最佳氮源为牛肉膏和蛋白胨。当温度高于35℃或低于15℃、p H值高于9或低于5时,菌株的生长会受到明显抑制,除磷率较低。同时研究表明,该菌株的生长会影响其生长环境基质的p H值,在一定范围内具有较强的p H值调节能力。该菌株能够有效利用乙酸钠和乙醇等小分子碳源获得较大生物量和较高的除磷效率,但是不能将铵盐作为唯一的氮源来利用。     

生物脱硫技术用于清洁燃料生产的初步研究

从高硫油田筛选的红球菌Rhodococcus sp.FS-2可以通过专一性断裂C-S键的"4S"途径将二苯并噻吩(DBT)转化成2-羟基联苯,从而降低油品中的硫含量.利用该菌株对DBT和汽油、柴油的脱硫研究结果表明,FS-2菌株对DBT及柴油中的有机硫有良好的选择性脱除作用,而且脱硫前后的烃类组分基本没有改变.说明该菌的脱硫过程不会破坏燃料油的有效成分,可以用于燃料油的深度脱硫.     

红球菌BAP-1对荧蒽的跨膜运输过程

利用同位素示踪法对红球菌BAP-1跨膜运输¹⁴C-荧蒽的过程进行了研究.结果表明在有ATP抑制剂NaN₃的存在下,红球菌BAP-1细胞膜内所结合的¹⁴C-荧蒽含量几乎无变化.结合对微生物体内包涵体的观察,说明当有ATP抑制剂存在的情况下,荧蒽无法通过细胞膜进入到微生物的体内.这表明若是荧蒽无法通过跨膜运输进入到红球菌细胞内,就不能得到有效的生物降解.在不同的底物浓度条件下,微生物对¹⁴C-荧蒽的跨膜运输过程是主动运输过程;在一定底物浓度条件下,菌体膜结合污染物的量会在一定的条件下达到饱和.结合米氏方程分析了红球菌BAP-1对¹⁴C-荧蒽的跨膜运输动力学过程,结果表明底物¹⁴C-荧蒽与微生物之间一直保持较高的亲和力,较高的亲和体系有助于跨膜运输过程的顺利进行.     

Physiological cellular responses and adaptations of Rhodococcus erythropolis IBBPo1 to toxic organic solvents

A new Gram-positive bacterium, Rhodococcus erythropolis IBBPo1（KF059972.1） was isolated from a crude oil-contaminated soil sample by enrichment culture method. R. erythropolis IBBPo1 was able to tolerate a wide range of toxic compounds, such as antibiotics（800–1000 μg/mL）,synthetic surfactants（50–200 μg/mL）, and organic solvents（40%–100%）. R. erythropolis IBBPo1 showed good tolerance to both alkanes（cyclohexane, n-hexane, n-decane） and aromatics（toluene, styrene, ethylbenzene） with logPOW（logarithm of the partition coefficient of the solvent in octanol–water mixture） values between 2.64 and 5.98. However, alkanes were less toxic for R. erythropolis IBBPo1 cells, compared with aromatics. The high organic solvent tolerance of R. erythropolis IBBPo1 could be due to the presence in their large genome of some catabolic（alkB, alkB1, todC1, todM, xylM）, transporter（HAE1） and trehalose-6-phosphate synthase（otsA1, KF059973.1） genes. Numerous and complex physiological cellular responses and adaptations involved in organic solvent tolerance were revealed in R. erythropolis IBBPo1 cells exposed 1 and 24 hr to 1% organic solvents. R. erythropolis IBBPo1 cells adapt to 1% organic solvents by changing surface hydrophobicity, morphology and their metabolic fingerprinting.Considerable modifications in otsA1 gene sequence were also observed in cells exposed to organic solvents（except ethylbenzene）.     

Screening and identification of bacterial strain producing (R)-1-phenyl-1,2-Ethanediol by efficient whole-cell catalytic reduction system北大核心CSCD

(R)-1-Phenyl-1,2-ethanediol [(R)-PED] is an important chiral intermediate used to synthesize pharmaceutical intermediates. The production of (R)-PED is of great practical significance. A novel bacterial strain HBU-SI7 isolated from soil samples was screened using a-hydroxyacetophenone (2-HAP) as substrate, which is capable of enantioselective reduction of 2-HAP to (R)-PED. HBU-SI7 was identified as Rhodococcus sp. by bacterial morphological observation and 16S rDNA analysis. The analysis of whole-cell catalytic system showed that the bioconversion of 2-HAP reached 96.2% in the two-phase reaction system (dibutyl phthalate/phosphate buffer = 1/3, V/V) with the substrate concentration of 3.0 g/L, and 99.3% of e.e. for (R)-PED was achieved. A new enantio selective reduction system with the whole cells of Rhodococcus sp. was established for efficient production of (R)-PED, which has potential research and application values. © 2018 Science Press. All rights reserved.     

红球菌J-5菌株降解聚乙烯醇的研究

从土壤样品中分离到一株能以聚乙烯醇(PVA)为唯一碳源、能源生长的纯菌株,经生理生化鉴定和16S rRNA基因序列分析,该菌株属于红球菌属(Rhodococcus sp.),对该菌株降解PVA的特性进行了研究.结果表明,该菌株降解PVA的适宜条件为10000mg/L PVA,25℃,摇床培养;此外,添加0.1%的酵母膏可以明显促进PVA的降解.在该条件下通气培养7d,可以降解58%的PVA,通过红外光谱分析PVA的代谢产物,说明PVA降解的中间产物带有羰基.