Degradation of SDS by psychrotolerant Staphylococcus saprophyticus and Bacillus pumilus isolated from Southern Ocean water samples.

Bioremediation of surfactants in water bodies holds significant ecological importance as they are contaminants of emerging concern posing substantial threats to the aquatic environment. Microbes exhibiting special ability in terms of bioremediation of contaminants have always been reported to thrive in extraordinary environmental conditions that can be extreme in terms of temperature, lack of nutrients, and salinity. Therefore, in the present investigation, a total of 46 bacterial isolates were isolated from the Indian sector of the Southern Ocean and screened for degradation of sodium dodecyl sulphate (SDS). Further, two Gram-positive psychrotolerant bacterial strains, ASOI-01 and ASOI-02 were identified with significant SDS degradation potential. These isolates were further studied for growth optimization under different environmental conditions. The strains were characterized as Staphylococcus saprophyticus and Bacillus pumilus based on morphological, biochemical, and molecular (16S RNA gene) characteristics. The study reports 88.9% and 93.4% degradation of SDS at a concentration of 100 mgL-1, at 20 °C, and pH 7 by S. saprophyticus ASOI-01 and B. pumilus ASOI-02, respectively. The experiments were also conducted in wastewater samples where a slight reduction in degradation efficiency was observed with strains ASOI-01 and ASOI-02 exhibiting 76.83 and 64.93% degradation of SDS respectively. This study infers that these bacteria can be used for the bioremediation of anionic surfactants from water bodies and establishes the potential of extremophilic microbes for the utilization of sustainable wastewater management.

Modulating the production of xylanase by Bacillus pumilus BS131 through optimization using waste fiber sludge / Modulando a produção de xilanase por Bacillus pumilus BS131 por meio da otimização usando lodo de fibra residual

Abstract In recent days, cheapest alternative carbon source for fermentation purpose is desirable to minimize production cost. Xylanases have become attractive enzymes as their potential in bio-bleaching of pulp and paper industry. The objective of the present study was to identify the potential ability on the xylanase production by locally isolated Bacillus pumilus BS131 by using waste fiber sludge and wheat bran media under submerged fermentation. Culture growth conditions were optimized to obtain significant amount of xylanase. Maximum xylanase production was recorded after 72 hours of incubation at 30 °C and 7 pH with 4.0% substrate concentration. In the nutshell, the production of xylanase using inexpensive waste fiber sludge and wheat-bran as an alternative in place of expensive xylan substrate was more cost effective and environment friendly.

Resumo Nos últimos dias, a fonte alternativa de carbono mais barata para fins de fermentação é desejável para minimizar o custo de produção. As xilanases têm se tornado enzimas atraentes como seu potencial no biobranqueamento da indústria de papel e celulose. O objetivo do presente estudo foi identificar a capacidade potencial na produção de xilanase por Bacillus pumilus BS131 isolado localmente usando lodo de fibra residual e farelo de trigo em meio de fermentação submersa. As condições de crescimento da cultura foram otimizadas para obter uma quantidade significativa de xilanase. A produção máxima de xilanase foi registrada após 72 horas de incubação a 30 °C e pH 7 com concentração de substrato de 4,0%. Resumindo, a produção de xilanase usando lodo de fibra residual de baixo custo e farelo de trigo como uma alternativa no lugar do substrato de xilano caro foi mais econômica e ecológica.

Modulating the production of xylanase by Bacillus pumilus BS131 through optimization using waste fiber sludge.

In recent days, cheapest alternative carbon source for fermentation purpose is desirable to minimize production cost. Xylanases have become attractive enzymes as their potential in bio-bleaching of pulp and paper industry. The objective of the present study was to identify the potential ability on the xylanase production by locally isolated Bacillus pumilus BS131 by using waste fiber sludge and wheat bran media under submerged fermentation. Culture growth conditions were optimized to obtain significant amount of xylanase. Maximum xylanase production was recorded after 72 hours of incubation at 30 °C and 7 pH with 4.0% substrate concentration. In the nutshell, the production of xylanase using inexpensive waste fiber sludge and wheat-bran as an alternative in place of expensive xylan substrate was more cost effective and environment friendly.

Isolated Phosphate-Solubilizing Soil Bacteria Promotes In vitro Growth of Solanum tuberosum L.

The capacity of four bacterial strains isolated from productive soil potato fields to solubilize tricalcium phosphate on Pikovskaya agar or in a liquid medium was evaluated. A bacterial strain was selected to evaluate in vitro capacity of plant-growth promotion on Solanum tuberosum L. culture. Bacterial strain A3 showed the highest value of phosphate solubilization, reaching a 20 mm-diameter halo and a concentration of 350 mg/l on agar and in a liquid medium, respectively. Bacterial strain A3 was identified by 16S rDNA analysis as Bacillus pumilus with 98% identity; therefore, it is the first report for Bacillus pumilus as phosphate solubilizer. Plant-growth promotion assayed by in vitro culture of potato microplants showed that the addition of bacterial strain A3 increased root and stems length after 28 days. It significantly increased stem length by 79.3%, and duplicated the fresh weight of control microplants. In this paper, results reported regarding phosphorus solubilization and growth promotion under in vitro conditions represent a step forward in the use of innocuous bacterial strain biofertilizer on potato field cultures.

Simulation of a surface spill of different diesel/biodiesel mixtures in an ultisol, using natural attenuation and bioaugmentation/biostimulation.

Accidents caused by leaks and/or spills on soils need to be addressed. Natural attenuation, biostimulation and bioaugmentation can be useful bioremediation strategies for decontamination processes in soils of diesel/biodiesel mixtures. The purpose of this study was to evaluate the degradation rate of the different fuels (B0, B20 and B100) in an ultisol under natural attenuation and biostimulation/bioaugmentation during 60 days of incubation in a controlled microcosm simulating a surface spill over soil. The degradation of different diesel/biodiesel mixtures was monitored for up to 60 days by dehydrogenase activity, respirometry by CO2 release, the most probable number of heterotrophic and degrading microorganism and gas chromatography. The bacterial inoculum employed for biostimulation/bioaugmentation strategy consisted of Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The two bioremediation strategies have showed great degradation rates. The natural attenuation was effective for B0 and B20 treatments. The addition of the bacterial consortium and macronutrients contributed to the increased degradation of pure biodiesel in relation to natural attenuation, with higher rates for CO2 release, enzymatic and degrading activity. It is suggested that the bacterial consortium has proven effective for presenting significant values for such parameters until the end of the 60-day incubation period.

Isolation, identification, and optimal cultivation of a marine bacterium antagonistic to Magnaporthe grisea.

In this paper, a plate confrontation method was used to isolate bacteria antagonistic to the rice blast fungus Magnaporthe grisea from samples collected from China's Dalian Bay. The antagonist strain LM-031 was obtained. We studied this strain's morphological, physiological and biochemical characteristics and analyzed its 16S rDNA sequence. We compared the effects of different culture conditions (type of media, carbon and nitrogen source, incubation temperature and time, and initial pH value) on the inhibitory effect against M. grisea. Strain LM-031 was preliminarily identified as Bacillus pumilus and was found to strongly inhibit M. grisea, especially when grown on BPY medium at an initial pH 7 for 72 h at 30°C. The optimum carbon and nitrogen sources for growth were lactose and peptone, respectively. The most suitable carbon and nitrogen sources for production of active substances were glucose and NH4Cl, respectively. Our results show that development and utilization of B. pumilus LM-031 has great potential for biological control of M. grisea.