Ge S.,Wenzhou University |
Ge S.,Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection |
Ge S.,Shanghai Benegene Biotechnology Co. |
Zhou M.,Wenzhou University |
And 3 more authors.
Journal of Environmental Management
Bioremediation has been found to be a useful method for removing hexavalent chromium (Cr(VI)), which is very toxic, from wastewater. Two strains of bacteria that were able to reduce Cr(VI) effectively were isolated from Cr(VI) contaminated soil samples and identified as Brevibacterium sp. K1 and Stenotrophomonas sp. D6, respectively, based on 16S rRNA gene sequence analyses. Brevibacterium sp. K1 and Stenotrophomonas sp. D6 could grow in Luria-Broth medium containing K2Cr2O7 at 1000 and 1600mg/L, respectively, and they completely reduced the Cr(VI) in LB medium containing K2Cr2O7 at 200mg/L within 72h. Further analyses revealed that permeabilized K1 and D6 cells reduced Cr(VI) more effectively than did the resting cells. Triton X-100 was the best permeabilizing agent that was tested. The permeabilized cells of both strains could completely reduce Cr(VI) in industrial wastewater twice before needing to be replenished. The results suggested that these chromate-reducing bacteria are potential candidates for practical use biotreating industrial effluents containing Cr(VI) with Stenotrophomonas sp. D6 being the more effective bacterium. D6 could remove Cr(VI) from wastewater repeatedly. K1 could remove Cr(VI) from wastewater repeatedly. D6 was superior to Brevibacterium sp. K1 at Cr(VI) reduction. © 2015 Elsevier Ltd. Source
Zheng W.-H.,Wenzhou University |
Zheng W.-H.,Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection |
Lin L.,Wenzhou University |
Liu J.-S.,Wenzhou University |
And 4 more authors.
Journal of Thermal Biology
Temperature is an important environmental cue for the regulation of thermogenesis in small birds. We tested the hypothesis that a small passerine, the Chinese bulbul Pycnonotus sinensis can decrease thermogenesis in response to warmer temperatures by decreasing body mass, the organ mass and changing physiological and biochemical processes in the liver and muscle. Captive Chinese bulbuls decreased in body mass and basal metabolic rate (BMR) during 4 weeks of acclimation to 30±1. °C. They also showed a decrease in liver, kidney and small intestine mass and reduced mitochondrial state-4 respiration and cytochrome C oxidase (COX) activity in the liver and muscle compared to 10±1. °C. Furthermore, BMR was positively correlated with body mass, organ mass (liver, kidney, small intestine and entire digestive tract), and mitochondrial state-4 respiration and cytochrome C oxidase (COX) activity in the liver and muscle. These results indicate that changes in body mass, organ mass and respiratory enzyme activity are mechanisms by which Chinese bulbuls adapt to warmer temperatures. The data support the hypothesis that such physiological flexibility is ubiquitous in birds. © 2013 Elsevier Ltd. Source
Zhu L.,Wenzhou University |
Cao J.,Wenzhou University |
Zhang W.,Wenzhou University |
Ge S.,Wenzhou University |
And 9 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae
A chromium(VI)-tolerant bacterial strain, Y73, was isolated from the Cr(VI)-containing wastewater-contaminated soil near the industrial area of Wenzhou, Zhejiang Province. Y73 was identified as Staphylococcus on the basis of its 16S rRNA sequence analysis. The strain could tolerate 1600 mg·L-1 Cr(VI) added as K2Cr2O7 in LB medium. It was an aerobic strain but could reduce Cr(VI) to Cr(III) under three conditions of oxygen stress: aerobic, anaerobic and aerobic growth followed by facultative anaerobic conditions. The highest Cr(VI) reduction rate was observed under aerobic growth followed by facultative anaerobic condition, with 83% of 1000 mg·L-1 Cr(VI) reduced within 96 h. To our knowledge, there is few report about the reduction of Cr(VI) by bacterial strain under these three conditions. Moreover, the reduction of Cr(VI) occurred over a wide range of pH (5~11) and temperature (10~50°C) with the optimum performance at pH 7 and 30°C. The increased Cr(VI) reduction rate was observed with an increase of inoculums of the strain. However, the effects of the increasing inoculums on the Cr(VI) reduction became no obvious when the inoculums were over 10%. The effect of most of the tested metals (each with 50 mg·L-1) on the Cr(VI) reduction was not significant. The results indicated that the strain possesses distinct capability for the Cr(VI) removal and the potential for application in the treatment of chromate(VI)-contaminated wastewaters. Source