Papers by Author: Min Zhao

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Authors: Chun Lei Wang, Min Zhao, Xing Dong Wei, Tai Lun Li, Lei Lu
Abstract: Treatment of xenobiotic compounds such as textile dyes with bacterial laccases is limited to the acid pH range and moderate temperatures. A bacterial strain, designated as WD23, was isolated from forest soil using Luria-Bertani medium supplemented with 0.4 mmol/L Cu2+. The isolated strain was identified as Bacillus subtilis by physiological and biochemical tests and 16S rDNA sequence analysis. Here we charactered the spore-bound laccase of B. subtilis WD23 and used the laccase to decolorize dyes. The spores of the strain showed laccase-like activity, oxidizing syringaldazine, 2,6-dimethoxyphenol and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonate acid)(ABTS). The optimum pH and temperature for the spore-bound laccase were 6.8 and 60°C, respectively. It also showed higher stabilities over a broad pH range, the pH half-life was more than 6 months at pH 6.8. The spore laccase could efficiently decolorize 50~90% of anthraquinone and azo dyes in 24 h. The spore laccase can play an important role in bioremediation.
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Authors: Dai Zong Cui, Min Zhao, Guo Fang Li, Xiao Xu Gu, Guang Ying Hui Du, Chun Lei Wang
Abstract: In this study, a new strain was isolated by us based on its efficiency to decolorize azo dyes. Identification of this isolate by 16S rDNA technique revealed that the strain belonged to Escherichia, and clustered within Escherichia coli. According to this, we renamed our strain as E. coli CD-2. The strain CD-2 could decolorize azo dyes effectively under aerobic conditions. CD-2 exhibited good decolorization ability in the pH range from 3 to 11, temperature from 30°C to 42°C and salinity from 1% to 4%. CD-2 could decolorized different azo dyes (methyl red, Congo red, eriochrome black T and eriochrome red B) within 16h, and the decolorizing rate were 97.15%, 86.03%, 56.92% and 81.14%, respectively. This degradation potential increased the applicability of this strain for the azo dye removal.
381
Authors: Fan Zhang, Min Zhao, Wei Wang, Tie Feng Hu
Abstract: Bifidobacterium bifidum were encapsulated as fresh cultures in water insoluble food grade microcapsules by emulsification–internal gelation technique, using gelatin, pectin, alginate and chitose as immobilization material. The optical photomicroscope photograph and laser scanning confocal microscope photograph shows that the microcapsules obtained by this method has narrow size distribution (10-20 μm). Survival of Bifidobacterium bifidum in microcapsules was 109cfu•g-1 , and the embedding ratio was 72.32%. The survival was remaining more than 108cfu•g-1 after exposure to gastric acid and bile acid, which implies that the microcapsules expressed superior acid resistance. These microcaosules were disaggregation subtotal after 15 min in simulated intestinal juices, and the release rate was 96%. The survival was 108 cfu•g-1 at room temperature after 1 year by classic accelerated test. The results indicate that encapsulation of Bifidobacterium bifidum in alginate microcapsules is a good approach to prolonging viability.
1481
Authors: Ning Zhang, Min Zhao, Chun Lei Wang, Guang Ying Hui Du
Abstract: Bacillus subtilis cotA gene which was designed According to GenBank. cotA gene was transformed to Escherichia coli BL21(DE3). The recombined CotA protein was expressed by IPTG induced method. The CotA protein was stained red by syringaldazine after Native-PAGE.The effects of the condition of induction expression on enzyme production of recombinant Escherichia coli were investigated. The result showed that the highest enzyme activity of recombinant CotA could be achieved under the following conditions: the concentration of IPTG was 1.0 mmol L-1, IPTG was added to the culture given a final concentration of 1.0 mol L-1 when the OD600 of culture reached 1.0, induction time was 12 h at 25°C. The CotA laccases could decolorize Remazol brilliant blue R (RBBR) and Congo red with 87% and Isatin and Crystal Violet with 55%. The result indicated that the CotA laccase had the potential to be industrial enzyme.
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Authors: Chun Lei Wang, Min Zhao, De Bin Li, Dai Zong Cui, Hong Yi Yang, Lei Lu, Xing Dong Wei
Abstract: The strain Bacillus sp. WD23 exhibiting laccase activity was screened from forest soil. The M9 medium containing Cu2+ was used for enriching and isolating bacterial strains capable of oxidizing syringaldazine (SGZ). One isolated strain was identified as Bacillus subtilis WD23 based on the results of physiological and biochemical tests and 16S rDNA sequence analysis. The strain WD23 could grow at temperatures ranging from 20 to 55°C and showed optimum growth temperature and pH at 25°C and 7.0, respectively. The sporulation rate of the strain clearly correlated well with the laccase activity. The temperature half-life of the spore laccase was 2.5 h at 80°C and the pH half-life was 15 d at pH 9.0. Its spore laccase could decolorized 50~90% of Remazol brilliant blue R (RBBR), alizarin red, congo red, methyl orange and methyl violet, which suggests the potential application of spore laccase in dyestuff treatment.
725
Authors: De Bin Li, Lei Lu, Min Zhao
Abstract: Bacterial strains with chlorimuron-ethyl degrading ability were isolated for bioremediation of contaminated soil. Six strains were obtained from chlorimuron-ethyl contaminated soil by enrichment cultivation. HPLC analysis indicated that two strains (A4 and A5) demonstrated high degradation efficiency than other strains. More than 61% of chlorimuron-ethyl was degraded by the two strains after 24 h. Based on the results of biochemical tests and 16S rDNA sequence analysis, the strain A4 and A5 were identified as Bacillus licheniformis and B. cereus, respectively. The cultivation conditions of the two strains were optimized to increase the biomass production.
913
Authors: Jie Zhang, Yong Qiang Liu, Jing Ren, Bin Song Wang, Min Zhao
Abstract: The optimal conditions of immobilization were obtained: the optimization of crosslinking agent concentration 10%, crosslinking time 2 hours、crosslinking temperature 40°C, pH 6.0, enzyme dilute multiples 500, PEB ion concentration 2.0M, immobilization time 6h and immobilization temperature 30°C, respectively.
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