Diesel degradation and biosurfactant production by Gram-positive isolates

Abstract

Accidental leakages during hydrocarbon fuels transportation and other activities are inevitable, making these hydrocarbons the most common global environmental pollutants. Current understanding in diesel degradation involves the study of Gram-negative microorganisms. Seven Gram-positive and one Gram-negative diesel degrading bacteria isolated from contaminated soil were used in this study. The overnight bacterial cultures were standardized and transferred into Bushnell-Haas medium supplemented with glucose and incubated at 30°C at 160 rpm for 48 h. The level of diesel degradation was determined using gravimetric analysis. Cell numbers were calculated using total heterotrophic plate count. All isolates were capable of degrading 70 -80% of n-paraffin whilst isolates D2, D9, D10 and DJLB possessed better abilities of diesel degradation at 65.4 -83.12% under the standard conditions. Diesel degradation rates and microbial cell number, increased with an increase in glucose composition. The addition of glucose to the liquid medium had a positive effect, with an increase in growth of the isolates thus leading to significantly (p < 0.05) higher percentages of diesel degradation and greater emulsification activity. The ability of Gram-positive bacteria to degrade diesel increased in a comparable trend as its biosurfactant production increased. The E 24 index was highest at 87.6% for isolate D9. Isolates D2, D9 and D10, were identified as Paenibacillus sp. whilst isolate DJLB was found to belong to Stenotrophomonas sp. This study clearly demonstrates that Gram-positive biosurfactant producing bacteria are effective in diesel degradation.

Motor oil wastewater treatment in a packed bed bioreactor using immobilized native microbial consortium

“…The remaining amount of hydrocarbons from the media culture was evaluated 14 days after the biodegradation process. The residual hydrocarbons were extracted using a gravimetric method with 100 mL of culture media and 100 mL hexane in a Soxhlet apparatus (Ganesh and Lin, 2009;Sonwani et al, 2020).…”

“…The experiments were done by triplicate using the same bioreactor and initial conditions. During the operation of the PBBR, the remaining amount of WMO from the wastewater was evaluated every seven days using a gravimetric method with 100 mL of synthetic wastewater and 100 mL hexane in a Soxhlet apparatus (Ganesh and Lin, 2009;Sonwani et al, 2020).…”

Exploiting bacterial isolates for diesel degrading potential under in vitro conditions

“…In order to nd out the microbial isolates possessing hydrocarbon degrading capabilities . Primary and secondary screenings Ganesh and Lin (2009); Marquez-Rocha et al ( 2001); Chang (1998) of hydrocarbon degrading microbes were performed. Soil suspension was made by mixing with 1g soil in 10 ml Bushnell and Hass Broth (BH broth) conditionedwith 1% (v/v) lter-sterilized diesel as the sole source of carbon.…”

“…Primary screening, soil suspension was inoculated in Bushnell Hass broth supplemented with 1% lter sterilized diesel incubated on orbital shaker incubator for 24 hours. Secondary screening was performed by Liquid-liquid extraction or the gravitational analysis method by Ganesh and Lin (2009) to evaluate percent hydrocarbon degradation potential of the bacterial isolates with respect to the baseline control (set as on 0 Day). For extraction of hydrocarbon, 20 ml of culture broth (BH Broth) was mixed with 20 ml petroleum ether: acetone (1:1) solvents in a gravimetric funnel and was shaken vigorously to get a single emulsi ed layer.…”

Sustainable Low-Cost Surfactin Production And Optimization By Bacillus Subtilis SNW3, Product Characterization, And Its Suitability For Plant Growth Promotion And Bioremediation of Crude Oil

“…The soil content of each pot was tilled twice a week for aeration with moisture maintenance at 60% and temperature of 28-30 ºC, providing all those conditions that are appropriate for crude oil-degrading microbes present in the soil. After that soil samples of 10 g were collected from different areas of the plastic pots at the 30,60, 90th day and were gravimetrically determined using formula given by Ganesh and Lin (2009). The obtained results were analyzed statistically with the use of STATISTICA software, one-way ANOVA (version 8.1).…”