Molecular identification and biosurfactant production by Pseudomonas spp and Alcaligenes spp from selected automobile workshops in Ilorin, Nigeria

Abstract

This study investigated production of biosurfactants (surface-active agents) produced by microorganisms like Pseudomonas and Alcaligenes isolated from soil samples in automobile repair workshops in Ilorin. Soil samples were collected from twenty-one (21) randomly selected mechanic workshops across the three local government areas in Ilorin. Physicochemical examination of the sampled soil as well as isolation of bacteria from the soil was done using Pseudomonas isolation Agar after which biochemical tests were performed on the isolated bacteria. The organisms were identified using molecular tools. Isolated Pseudomonas species and Alcaligenes species were screened for biosurfactants production using various screening methods, including haemolytic assay (α-, β-, and γ) and emulsification index. The results were statistically analyzed using one-way ANOVA and Duncan’s test (p < 0.05). Obtained results are: soil pH (6.03-7.50), electrical conductivity (2.19-90.71), organic carbon (0.78-1.63), organic matter (1.23-7.11), sand (6.47-84.6), silt (5.77-16.04) clay (5.07-12.24) and moisture content (11.3-14.10). Levels of significant differences (p < 0.05) were observed statistically. Among the seven isolates onlyPseudomonas aeruginosa-PQ6 was γ-haemolytic. For drop collapse assay, Alcaligenefaecalis-CPO6 showed no reaction. Three of the seven bacterial isolates exhibited the highest emulsification activity: Alcaligenes faecalis-CPO1 (67% Petrol, 65% Engine-oil, 64% Kerosene), Pseudomonas aeruginosa-OR9 (60% Petrol, 67% Engine-oil, 63% Kerosene) and Pseudomonas aeruginosa-MH7 (71% Petrol, 65% Engine-oil, 64% Kerosene). They show promise as biosurfactant producing bacteria. The effective isolates can be utilized for biosurfactant production as sustainable alternatives to synthetic surfactants and hence will help to clean up oil polluted environment.