Aims: Oil sludge is one of pollutant sources in the environment. Bacterial abundance, interaction, and compatibility of environmental factors ensure the success of biodegradation. The purpose of this study was to determine the effectiveness of bacterial consortium in degrading oil sludge using bioslurry method. Methodology and results: The research design used was completely randomized design 4×5 with variation of bacterial consortium concentration and incubation time. Composition of contaminant and liquid phase in bioslurry method was 1:9 ratio with aeration, at room temperature. The liquid phase comprises distilled water with the addition of 2% (v/v) of molasses as nutrient for bacterial growth. Bacterial growth was evaluated using the Total Plate Count (TPC) method. Total Petroleum Hydrocarbon (TPH) measurements were evaluated using the gravimetric method while the oil sludge hydrocarbon component was evaluated by Gas Chromatography Mass Spectrophotometry (GCMS). The pH and temperature data were analyzed descriptively while TPC and TPH data were analyzed using Two Way ANOVA (α=0.05). The bacterial consortium could grow on oil sludge hydrocarbon substrate with a range of temperature of 29 °C-32 °C and an optimum pH of 7. Biodegradation of TPH was 70.48% at consortium concentration of 15% in 14 days of incubation. Conclusion, significance and impact of study Biodegradation of oil sludge using a bacterial consortium by bioslurry method is one of the effective methods to reduce pollutants in the management of oil sludge.

Aims: This study aims to produce Achromobacter biosurfactant in nutrient-rich and nutrient-limited media. Methodology and results: This study conducted fermentation on nutrient-rich and nutrient-limited media using a minimal salt medium (MSM). Dextrose and sodium citrate were used as sole carbon supplemented with 0.5% yeast extract for nutrient-rich media, while nutrient-limited media used molasses and rice straw hydrolysate (RSH) at variations of concentrations of 100 ppm and 200 ppm. The research was performed over 120 h and evaluated from growth response, surface tension and emulsification activity. The study revealed that the best surface tension value was when 2% (w/v) sodium citrate was used as C-source and 0.5% (w/v) yeast extract as N-source, after 72 h upon incubation at 30 °C/120 rpm having 45.45 ± 2.19 mN/m with emulsification activity 24.54 ± 3.42%. Whereas the best result of the nutrient-limited medium was obtained by RSH at a concentration of 200 ppm having 48.86 ± 5.36 mN/m. Conclusion, significance and impact of study The experiment showed that nutrient-limited medium from rice straw hydrolysate could compete with the nutrient-rich medium. The use of rice straw will contribute to the reduction of biosurfactant production costs and valorisation of agricultural waste.
Achromobacter denitrificans ; Surface-Active Agents