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Bacterial Diversity in Selenium Reduction of Agricultural Drainage Water Amended with Rice Straw
Author(s) -
Siddique Tariq,
Okeke Benedict C.,
Zhang Yiqiang,
Arshad Muhammad,
Han Suk K.,
Frankenberger William T.
Publication year - 2005
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0217a
Subject(s) - firmicutes , temperature gradient gel electrophoresis , straw , oryza sativa , proteobacteria , actinobacteria , bacteria , drainage , biology , selenium , agronomy , botany , environmental chemistry , chemistry , 16s ribosomal rna , ecology , biochemistry , genetics , organic chemistry , gene
Bacterial reduction of the Se oxyanions selenate [Se(VI)] and selenite [Se(IV)] to elemental selenium [Se(0)] is an important biological process in removing Se from drainage water. This study was conducted to characterize the molecular diversity of bacterial populations involved in Se reduction of drainage water amended with rice ( Oryza sativa L.) straw and also to monitor the bacterial community shifts during the course of the study. Selenate was removed in the drainage water by the bacteria 5 to 6 d after addition of rice straw. Six Se(VI)‐ and 32 Se(IV)‐reducing bacteria were isolated from rice straw containing sterilized drainage water. Three Se(VI)‐ and two Se(IV)‐reducing bacteria were also isolated from the drainage water. Identification of Se(VI)‐ and Se(IV)‐reducing bacteria by 16S rDNA sequence analysis showed a broad phylogenetic diversity in Se‐reducing assemblages. Three major phyla (Proteobacteria, Actinobacteria, and Firmicutes) of bacterial domain with numerous classes, orders, and families constituted the Se‐reducing bacterial community. We documented changes in the composition of bacterial assemblages in the drainage water amended with rice straw using polymerase chain reaction (PCR)–denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. The Shannon–Weaver index ( H ′) revealed higher bacterial diversity at Day 6 in the sterilized and Day 4 in the nonsterilized drainage water amended with rice straw. The results of this study suggest that rice straw, a good source of carbon and energy, harbors a wide range of bacteria useful in Se reduction and may be used in removing Se from drainage water.