共生细菌对盐生小球藻富集和转化砷酸盐的影响  

Effects of a Symbiotic Bacterium on the Accumulation and Transformation of Arsenate by Chlorella salina

作　　者：许平平[1] 刘聪[1] 王亚[1] 郑燕恒 张春华[2] 葛滢[1] 

机构地区：[1]南京农业大学资源与环境科学学院,江苏省海洋生物学重点实验室,南京210095 [2]南京农业大学生命科学实验中心,元素与生命科学示范实验室,南京210095

出　　处：《环境科学》2016年第9期3438-3446,共9页Environmental Science

基　　金：国家自然科学基金项目(41371468,31400450);中央高校基本科研业务费项目(KJQN201533)

摘　　要：藻菌共生体系在污水处理和环境修复等方面具有良好的应用前景.为探讨共生细菌对小球藻富集和转化砷酸盐[As（Ⅴ）]的影响,本研究采用批次培养实验,设置0～750μg·L^-1As（Ⅴ）,暴露7 d后测定无菌和带菌的盐生小球藻（Chlorella salina）对砷的吸收、吸附和形态转化.小球藻的共生细菌经分离、培养与16S rRNA鉴定,确定为盐单胞菌（Halomonas sp.）.该菌存在时,小球藻细胞对砷的吸附显著增加,但对砷的吸收显著降低,从而降低了As（Ⅴ）对小球藻的毒性效应.无菌和带菌小球藻胞内的砷形态均以As（Ⅴ）为主;前者As（Ⅲ）的比例为8.99%～11.52%,后者则检测到少量的一甲基砷（MMA）和二甲基砷（DMA）（0.02%～0.04%）.盐单胞菌单独培养时,培养液中的砷以As（Ⅲ）为主要形态,As（Ⅴ）所占比例为7.59%～26.80%,表明该细菌具有较强的砷酸盐还原能力.不同浓度As（Ⅴ）暴露7 d后,带菌小球藻对溶液中砷的去除率为19.81%～41.08%,高于盐单胞菌（5.14%～14.62%）和无菌小球藻（14.98%～21.08%）的去除率.共生的盐单胞菌促进了盐生小球藻对砷的富集,表明藻菌共生可增强砷污染水体的生物修复效果.Algae-bacteria consortia may be potentially applied in wastewater treatment and environment remediation. In this study,in order to investigate effects of a symbiotic bacterium on the accumulation and transformation of arsenate[As（ Ⅴ） ] by Chlorella salina,we used batch cultures to determine the uptake,adsorption and transformation of As by axenic and non-axenic C. salina exposed to 0-750 μg·L^-1As（ Ⅴ） for 7 d. The symbiotic bacterium of C. salina was confirmed to be Halomonas sp. after isolation,cultivation and16 S rRNA identification. The bacterial presence markedly increased the adsorption of As in C. salina,but it markedly reduced the absorption and the toxic effect of As（ Ⅴ）. Arsenate was the major arsenic species in the cells of axenic and non-axenic C. salina. The proportion of arsenite[As（ Ⅲ） ] was 8. 99%-11. 52% in the axenic microalga whereas a small quantity of monomethylarsonous acid（ MMA） and dimethylarsinous acid（ DMA）（ 0. 02%-0. 04%） were detected in the non-axenic counterpart. As（ Ⅲ） dominated the As speciation in the bacterial culture and the percentage of As（ Ⅴ） was 7. 59%-26. 80%,indicating that this symbiotic bacterium had a strong As（ Ⅴ） reducing ability. The As removal rate（ 19. 81%-41. 08%） by non-axenic C. salina was higher than the bacterium alone（ 5. 14%-14. 62%） and axenic C. salina（ 14. 98%-21. 08%） after 7 d As（ Ⅴ） exposure. The symbiotic Halomonas sp.promoted the accumulation of As by C. salina,indicating that algae-bacteria consortia might enhance the bioremediation of As contaminated water.

关 键 词：小球藻 共生细菌 砷酸盐 吸收 吸附 形态 

分 类 号：X171.5[环境科学与工程—环境科学]