TY - JOUR
T1 - Selection of salt tolerant purple nonsulfur bacteria producing 5-aminolevulinic acid (ALA) and reducing methane emissions from microbial rice straw degradation
AU - Nunkaew, Tomorn
AU - Kantachote, Duangporn
AU - Nitoda, Teruhiko
AU - Kanzaki, Hiroshi
N1 - Funding Information:
This work was supported by Thailand Research Fund, Royal Golden Jubilee Ph.D. Program , Grant No.: PHD/0200/2551 and partly supported by Graduate School, Prince of Songkla University . We would like to thank Research and Development Office and Dr. Brian Hodgson, Prince of Songkla University for assistance with the English.
Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2015/2/1
Y1 - 2015/2/1
N2 - Saline soil is one major problem that causes low productivity on rice, while paddy fields are also one source of methane (CH4) emissions that can have a considerable impact on global warming. By using purple nonsulfur bacteria (PNSB) it is possible to overcome both these serious problems because PNSB produce 5-aminolevulinic acid (ALA), a compound that reduces salt stress for plants, and they are also good competitors for methanogens in the paddy fields. Therefore, the objective of this study was to select salt resistant PNSB with an ability to release ALA and reduce CH4 emissions. The PNSB isolates used were obtained from saline paddy fields in southern Thailand and the best were selected on the basis of their good growth under conditions of aerobic dark and anaerobic light while being salt tolerant, released ALA and reduced CH4 emissions under microaerobic light conditions. Among the 272 PNSB isolates, TN114 was the best ALA producer while PP803 was the best to reduce CH4 emissions. Both selected PNSB strains grew well in glutamate acetate (GA) broth containing NaCl up to 6.00% but 0.25% NaCl was their optimal concentration for growth. Under salt stress with 0.25% NaCl, the strain TN114 released 25.63μM ALA in GA broth. In scaled-up experiments, when it was mixed with native soil flora in rice straw broth the strain TN114 released 13.44μM ALA and the strain PP803 reduced CH4 emissions by 88.41%. These two strains were identified as Rhodopseudomonas palustris according to both traditional and 16S rRNA identifications. Overall the results demonstrated that they had a good potential as plant growth stimulating bacteria under salt stress, due to the release of ALA and also reduce CH4 emissions.
AB - Saline soil is one major problem that causes low productivity on rice, while paddy fields are also one source of methane (CH4) emissions that can have a considerable impact on global warming. By using purple nonsulfur bacteria (PNSB) it is possible to overcome both these serious problems because PNSB produce 5-aminolevulinic acid (ALA), a compound that reduces salt stress for plants, and they are also good competitors for methanogens in the paddy fields. Therefore, the objective of this study was to select salt resistant PNSB with an ability to release ALA and reduce CH4 emissions. The PNSB isolates used were obtained from saline paddy fields in southern Thailand and the best were selected on the basis of their good growth under conditions of aerobic dark and anaerobic light while being salt tolerant, released ALA and reduced CH4 emissions under microaerobic light conditions. Among the 272 PNSB isolates, TN114 was the best ALA producer while PP803 was the best to reduce CH4 emissions. Both selected PNSB strains grew well in glutamate acetate (GA) broth containing NaCl up to 6.00% but 0.25% NaCl was their optimal concentration for growth. Under salt stress with 0.25% NaCl, the strain TN114 released 25.63μM ALA in GA broth. In scaled-up experiments, when it was mixed with native soil flora in rice straw broth the strain TN114 released 13.44μM ALA and the strain PP803 reduced CH4 emissions by 88.41%. These two strains were identified as Rhodopseudomonas palustris according to both traditional and 16S rRNA identifications. Overall the results demonstrated that they had a good potential as plant growth stimulating bacteria under salt stress, due to the release of ALA and also reduce CH4 emissions.
KW - 5-Aminolevulinic acid
KW - Methane emissions
KW - Purple nonsulfur bacteria
KW - Rice straw
KW - Saline paddy fields
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U2 - 10.1016/j.apsoil.2014.10.005
DO - 10.1016/j.apsoil.2014.10.005
M3 - Article
AN - SCOPUS:84908632084
VL - 86
SP - 113
EP - 120
JO - Applied Soil Ecology
JF - Applied Soil Ecology
SN - 0929-1393
ER -