Life Cycle Assessment of the Environmental Impact of Biosurfactant Production from Oil Waste by a Diculture of Azotobacter vinelandii and Pseudomonas sp.

Abstract

This study is aimed at carrying out a life cycle assessment of the environmental impact of biosurfactant production from oily waste by a diculture of Azotobacter vinelandii and Pseudomonas sp. The methodology used was the life cycle assessment according to the ISO 14-040 standard. The microorganisms used in the study were also isolated from the environment. The biosurfactant produced were quantified and the CO2 and NH3 that were produced were quantified also. The life cycle assessment as a gate – to – gate assessment was considered in this study. Two impact categories were selected for their relevance (global warming, and acidification/eutrophication potentials). The functional unit used for the impact analysis was based on the production of 1000 Kg of biosurfactant. The result showed that during the bioprocess of the biosurfactant production (by the diculture), the volume of CO2 evolved was 28.23 ± 5.08 cm3 , which is equivalent to 0.056 ± 0.01 g CO2 per 100 ml of broth. In terms of g CO2/1000 Kg biosurfactant, 4545 ± 817.93 g CO2 were Produced in this bioprocess. The life cycle impact assessment of biosurfactant production by this consortium, based on global warming potential was 0.046 tonnes/1000 Kg biosurfactant. Other impact values calculated for acidification and eutrophication potentials were 0.008 tonnes/1000 Kg and 0.0014 tonnes/1000 Kg of biosurfactant. In this work also, the consortium produced 1.22 ± 0.04 mg biosurfactant per 100 ml of cell – free broth. However, the individual organisms Pseudomonas sp. and Azotobacter vinelandii produced 1.03 ± 0.02 and 0.08 ± 0.001 mg of biosurfactants per 100 ml cell-free broth respectively. These values when compared with the individual organisms shows that using a consortium for the Bioprocess is more sustainable.