Salt stress tolerance of methylotrophic bacteria Methylophilus sp. and Methylobacterium sp. isolated from coal mine spoils.
Two methylotrophic strains of Bina coalmine spoil BNV7b and BRV25 were identified based on physiological traits and 16S rDNA sequence as Methylophilus and Methylobacterium species.' The strains exhibited similar carbon utilization but differed in N utilization and their response to the metabolic inhibitors. Methylophilus sp. was less tolerant to salt stress and it viability declined to one tenth within 4 h of incubation in 2M NaCI due to membrane damage and leakage of the intracellular electrolytes as evident from malondiaaldehyde (MDA) assay. In 200 mM NaCI, they exhibited increased superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity while in 500 mM NaCI, enzyme activities declined in Methylophilus sp. and increased in Methylobacterium sp. Among exogenously applied osmoprotectants proline was most efficient; however, polyols (mannitol, sorbitol and glycerol) also supported growth under lethal NaCI concentration.
Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU).
Deen Dayal
DD
Giri
Department of Botany, Banaras Hindu University, India
Ajay
A
Kumar
Department of Botany, Banaras Hindu University, India
Prabhu Nath
PN
Shukla
Department of Botany, Banaras Hindu University, India
Ritu
R
Singh
Department of Botany, Banaras Hindu University, India
P K
PK
Singh
Department of Botany, Banaras Hindu University, India
Kapil Deo
KD
Pandey
D001426:Bacterial Proteins / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D003031:Coal / Q000032:analysis / Q000382:microbiology; D020580:Methylobacterium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D020629:Methylophilus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D012965:Sodium Chloride / Q000378:metabolism*; D012988:Soil Microbiology; D013482:Superoxide Dismutase / Q000378:metabolism
D001426:Bacterial Proteins; D003031:Coal; D012965:Sodium Chloride; D002374:Catalase; D013482:Superoxide Dismutase