Cold-adapted halotolerant Rhodococcus sp. BGI-11, a potential candidate for biotechnological applications

摘要

Rhodococcus sp. BGI-11 was isolated among 7 otherpsychrotrophic bacteria from ice of Batura glacier in the mighty Karakoram Range. Strain BGI-11 was selected among the rest of glacial isolates on the basis of its variable growth characteristics as well as its ability to utilize hydrocarbons as carbon and energy source. Phylogenetic analysis using 16S rRNA gene revealed the strain is most closely related to Rhodococcuserythropolis with a similarity index of 99.76%. BGI-11 was able to grow at a temperature range of 4-35°C, pH 4-11 and salinity up to 8% (w/v). Results for carbon utilization revealed the strain is able to use glucose, sucrose, maltose, galactose and lactose sugars. This strain also demonstrated the ability to use glycerol and molasses as growth substrates. The strain demonstrated growth in all the 8 culture media tested including, nutrient rich and the selective media. BGI-11 exhibited antimicrobial activity against the multidrug resistant strains of Bacillus sp. and candida albicans . BGI-11 also demonstrated positive activity for lipase and DNase enzymes. Antibiotic susceptibility pattern revealed the strain is resistant to methicillin and trimethoprim/sulfamethxazole while sensitive to imipenem, vancomycin, and ofloxacin. The most exciting physiological characteristics exhibited by this strain was its ability to use long chain hydrocarbon hexadecane as a carbon substrate. Thus, the cold-adapted halotolerant Rhodococcus sp. BGI-11 can be used as a potential candidate for various biotechnological applications. BGI-11 can further be used for bioremediation of hydrocarbons in deep oceans, an environment also characterized by low temperature and moderate salinity.