酵母提取物对葡萄糖发酵生产生物破乳菌Alcaligenes sp. S-XJ-1的影响

以从石油污染的土壤中筛选出1株生物破乳菌Alcaligenes sp.S-XJ-1为对象,考察了以葡萄糖为碳源时添加酵母提取物对生物破乳菌菌体性质、破乳性能以及菌体元素组成的影响.结果表明,酵母提取物的投加能够有效提高生物破乳菌产量,在酵母提取物浓度为5 g.L-1时,生物破乳菌产量达到3.0 g.L-1,此时葡萄糖利用率亦达到最大的58%.随着酵母提取物的投加浓度的增大,培养得到的菌体破乳性能提高,在投加浓度为10 g.L-1时,破乳率达到76%;而培养得到的菌体C/N有所降低,对其菌体表面蛋白进行提取测定发现菌体总蛋白含量升高,这与FTIR分析破乳菌菌体表面蛋白质类物质提高的结论一致.推测该生物破乳菌菌体蛋白含量的提高增强了菌体的破乳性能,菌体蛋白类物质是影响其破乳性能的关键组分之一.     

一株耐盐苯酚降解菌的分离、鉴定及耐盐机制研究

从污泥样品中分离得到1株高效的耐盐苯酚降解菌,该菌株能够在温度20～30 ℃、pH5.0～9.0和盐度1％ ～ 10％范围内以苯酚为唯一碳源进行生长.通过形态、生理生化特性分析及16S rDNA序列分析,鉴定该菌株为Rhodococcus sp.,命名为W2.在温度30℃、pH =7.0、NaCl50g·L-1的条件下,菌株可耐受苯酚的最大浓度为700 mg·L-1.粗酶中检测到的邻苯二酚l,2-双加氧酶活性表明,菌株W2通过邻位开环断裂途径代谢苯酚.底物广谱性考察结果表明,菌株W2能够在高盐条件下利用苯甲酸、水杨酸等多种芳香化合物作为碳源生长.对耐盐机理进行的初步分析表明,细胞内甜菜碱和四氢嘧啶的含量随着盐浓度的增加而增大,说明四氢嘧啶和甜菜碱的积累是菌株W2抵抗高盐度的重要机制.     

Isolation and characterization of atrazine-degrading Arthrobacter sp. AD26 and use of this strain in bioremediation of contaminated soil

A bacterial strain (AD26) capable of utilizing atrazine as a sole nitrogen source for growth was isolated from an industrial wastewater sample by enrichment culture. The 16S rRNA gene sequencing identified AD26 as an Arthrobacter sp. PCR assays indicated that AD26 contained atrazine-degrading genes trzN and atzBC. The trzN gene of AD26 only differs from the trzN of Arthrobacter aurescens TC1 by one base (A→T at 907) and one amino acid (Met→Leu at 303). The specific activity of trzN of AD26 in crude cell ext...     

固定化泛菌对底泥中孔雀石绿的降解

用2%海藻酸钠对孔雀石绿高效降解菌Pantoea sp.EF192586菌株进行固定化包埋,研究固定菌对底泥中孔雀石绿的降解情况。研究结果表明:固定菌对底泥中不同浓度孔雀石绿均有降解,且0.45和0.95μg/g干重降解率更好,达80%。增加固定菌的投菌量可提高降解速率和降解率,但当投菌量增至1.5g后降解率不再增加。泥水系统中水量减少可以提高固定菌起始阶段的降解速率。当固定菌和光照联合作用时可以提高降解率。     

一株菲高效降解菌的环境适应性研究

生物降解是多环芳烃从环境中去除的主要途径,菲是一种典型的三环芳烃。本研究考察了一株能高效降解多环芳烃菲的鞘氨醇单胞菌GY2B在含河沙环境及不同盐度的人工海水环境中的生长特性与降解菲的情况。结果表明：河沙的加入对菌株GY2B的生长及其高效降解菲的性能均无明显影响,65 h可将起始浓度为100 mg/L的菲降解99.5%以上;而经过驯化后在添加85%人工海水的条件下该菌也仍可正常生长并高效降解菲,66 h可将起始浓度为100 mg/L的菲几乎完全降解。本研究结果可为菌株GY2B在受多环芳烃污染的河滩、河口及近海海洋环境修复中的应用提供参考依据。     

Isolation of a Pseudomonas Stutzeri strain that degrades 1,2,4-trichlorobenzene and characterization of its degradative plasmid

The genetic information encoding metabolic pathways for xenobiotic compounds in bacteria often resides on catabolic plasmids. The aim of the present work was to know the location of the genes for degrading 1,2,4-trichlorobenzen. In this paper a 1,2,4-trichlorobenzene-degrading strain THSL-1 was isolated from the soil of Tianjin Chemical Plant using 1,2,4-trichlorobenzene as the sole carbon source. The strain was identified as Pseudomonas stutzeri through morphologic survey and 16S rDNA sequence determination. A plasmid was discovered from strain THSL-1 by using the alkali lysis method. When the plasmid was transformed into E. coli. JM109 by the CaCl₂ method, the transformant could grow using 1,2,4-trichlorobenzene as the sole carbon source and had the degradation function of 1,2,4-trichlorobenzene. Therefore, it could be deemed that the plasmid carried the degradative genes of 1,2,4-trichlorobenzene. The average size of the plasmid was finally determined to be 40.2 Kb using selectively three kinds of restricted inscribed enzymes (HindIII, BamHI, and XholI) for single cutting and double cutting the plasmid pTHSL-1, respectively. __________ Translated from China Environmental Science, 2005, 25(4): 385–388 [译自: 中国环境科学]     

链霉菌(Streptomyces sp.)对吲哚废水的降解特性

链霉菌(Streptomycessp.)HJ02能以吲哚为唯一碳源生长,考察了初始吲哚质量浓度、外加碳源、温度、pH等对其降解效果的影响,探讨了该菌降解吲哚的动力学与机理.结果表明,链霉菌对吲哚有很强的耐受力,在pH=7、温度为30℃的条件下培养6d,初始浓度为300mg·L-1吲哚的降解率达到97.4%.菌株对吲哚的降解过程动力学符合Andrews方程.外加葡萄糖会抑制链霉菌降解吲哚的速率,葡萄糖与吲哚之间存在底物竞争抑制.紫外光谱与GC分析表明,吲哚的特征杂环被链霉菌破坏.     

Isolation,identification, Pb(Ⅱ) biosorption isotherms and kinetics of a lead adsorbing Penicillium sp. MRF-1 from South Korean mine soil

A heavy metal contaminated soil sample collected from a mine in Chonnam Province of South Korea was found to be a source of heavy metal adsorbing biosorbents. Chemical analyses showed high contents of lead (Pb) at 357 mg/kg and cyanide (CN) at 14.6 mg/kg in the soil. The experimental results showed that Penicillium sp. MRF-1 was the best lead resistant fungus among the four individual metal tolerant fungal species isolated from the soil. Molecular characterization of Penicillium sp. MRF-1 was determined using ITS regions sequences. E ects of pH, temperature and contact time on adsorption of Pb(II) by Penicillium sp. MRF-1 were studied. Favorable conditions for maximum biosportion were found at pH 4 with 3 hr contact time. Biosorption of Pb(II) gradually increased with increasing temperature. E cient performance of the biosorbent was described using Langmuir and Freundlich isotherms. Adsorption kinetics was studied using pseudo first-order and pseudo second-order models. Biosorbent Penicillium sp. MRF-1 showed the maximum desorption in alkali conditions. Consistent adsorption/desorption potential of the biosorbent in repetitive cycles validated the e cacy of it in large scale. SEM studies given notes on surface modification of fungal biomass under metal stress and FT-IR results showed the presence of amino groups in the surface structure of the biosorbent. In conclusion, the new biosorbent Penicillium sp. MRF-1 may potentially be used as an inexpensive, easily cultivatable material for the removal of lead from aqueous solution.     

Screening for a new Streptomyces strain capable of e cient keratin degradation

Keratinous wastes could be degraded by some microorganisms in nature. Native human foot skin （NHFS） was used as sole nitrogen source to screen microorganisms with keratin-degrading capability. From approximately 200 strains, a strain of Streptomyces sp. strain No. 16 was found to possess the strongest keratinolytic activity, and the total activity in the culture was 110 KU/ml with specific activity of 2870 KU/mg protein （KU： keratinase unit）. Substrate specificity test indicated that the crude keratinase could degrade keratin azure, human hair, cock feathers and collagen. The optimal pH of the crude keratinase ranged from 7.5 to 10 and the temperature ranged from 40℃ to 55℃. Metal chelating agent ethylenediamine tetraacetic acid obviously stimulated the keratinolytic activity but suppressed the proteolytic activity. To our knowledge, this is the first report on specific induction of keratinases by NHFS from an actinomycete. Moreover, excellent characteristics of its crude keratinase may lead to the potential application in waste treatment and recovery, poultry and leather industry, medicine, and cosmetic development.     

异养硝化细菌Bacillus sp. LY脱氮性能研究

研究了异养硝化细菌Bacillus sp. LY的脱氮性能.结果表明,Bacillus sp. LY是1株具有脱氮能力的异养硝化细菌.在NH⁺₄-N浓度分别为40、80和120 mg/L 3种情况下,120 h反应后,氨氮的去除率分别是100%、85.7%、73.7%,总氮的去除率分别是76.6%、53.4%、64.8%,在菌液初始浓度相同的情况下,随着NH⁺₄-N浓度的增加,细菌的硝化速率以及脱氮速率呈现下降的趋势.有机物浓度是影响Bacillus sp. LY脱氮性能的重要因素,低的有机物浓度会阻碍细菌脱氮性能的发挥,中的有机物浓度会促进细菌脱氮性能的发挥,使体系的脱氮效果达到最佳,高的有机物浓度并不能再次提升细菌的脱氮性能.在Bacillus sp. LY作用下,有机氮经过氨化作用生成氨氮,通过2条可能的途径转化为氮气.1条途径是氨氮先硝化生成亚硝酸盐与硝酸盐,然后反硝化生成氮气.另1条途径是氨氮被氧化生成羟胺,然后脱氢生成氧化亚氮并进一步转化为氮气.这些研究可为开发新型高效生物脱氮工艺提供参考.