RESUMEN
The draft genome sequence of Halomonas sp. strain ANAO-440 contains 3,866 predicted protein-coding sequences. This strain is capable of anaerobic arsenite oxidation and encodes an arxA-type arsenite oxidase within the arxB2AB1CD gene island. This genome sequence provides valuable information regarding the physiological diversity of Arx-dependent arsenite-oxidizing microorganisms.
RESUMEN
Bioremediation has been attracting researchers' attention to develop as a technique to remove the pollution of crude oil in the environment. However, more or stronger novel strains capable of crude oil removal are still required. In this study, the potential of five newly isolated bacterial strains for crude oil abatement was evaluated in the liquid medium and contaminated soil individually and as a mixed consortium. Raoultella ornithinolytica strain PS exhibited the highest ability and degraded up to 83.5% of crude oil. Whereas Bacillus subtilis strain BJ11 degraded 81.1%, Acinetobacter lwoffii strain BJ10 degraded 75.8%, Acinetobacter pittii strain BJ6 degraded 74.9%, and Serratia marcescens strain PL degraded only 70.0% of crude oil in the liquid media. The consortium comprising the above five strains degraded more than 94.0% of crude oil after 10 days of incubation in the liquid medium. The consortium degraded more than 65.0% of crude oil after 40 days incubation even in the contaminated soil. The five crude oil degrading strains, especially their consortium, exhibited a high capability to break down a wide range of compounds in crude oil including straight-chain alkanes, branched alkanes, and aromatic hydrocarbons. These strains, especially as consortia, have good potential of application in the remediation of crude oil-contaminated environments.
Asunto(s)
Bacterias/metabolismo , Consorcios Microbianos , Petróleo/metabolismo , Biodegradación Ambiental , Microbiología del SueloRESUMEN
Microbial arsenic transformation pathways associated with a saline lake located in northern Mongolia were examined using molecular biological and culturing approaches. Bacterial 16S rRNA gene sequences recovered from saline lake sediments and soils were affiliated with haloalkaliphiles, including Bacillus and Halomonas spp. Diverse sequences of arsenate respiratory reductase (arrA) and a new group of arsenite oxidase (arxA) genes were also identified. Pure cultures of arsenate-reducing Nitrincola strain and anaerobic arsenite-oxidizing Halomonas strain were isolated. The chemoorganotrophic Halomonas strain contains arxA gene similar to that of a chemoautotrophic arsenite-oxidizing Alkalilimnicola ehrlichii strain MLHE-1. These results revealed the diversity of arsenic transformation pathways associated with a geographically distinct saline system and the potential contribution of arx-dependent arsenite oxidation by heterotrophic bacteria.