The Bio-utilization of Used and Unused car Lubricants by Autochthonous Microorganisms

Abstract

The determination of the bio-utilization of used and unused car lubricants; engine oil, hydraulic and transition oil were analyzed using viable counts and spectrophotometric analysis. The oil samples were collected with 10 sterile containers from different mechanic workshops in Calabar; Unical workshop, designated as UNICAL Workshop (A), Akim (B), Mount Zion (C), Etta Agbor (D), and Ekpo Abasi (E). The spectrophotometric analysis revealed absorbance ranging from 2.16 to 2.69nm for engine oil, 0.57 to 1.21nm for hydraulic oil and 1.96 to 2.40nm for transition oil. The total heterotrophic counts of the used engine oil ranged from 1.2x1010 CFU/ml to 4.0x1010 CFU/ml; hydraulic oil ranged from 1.0x1010 CFU/ml to 2.2x1010 CFU/ml; Transition oil ranged from 1.0x1010 CFU/ml to 2.5x1010 CFU/ml. The THB counts of the unused oils had an average count of 1.0x10110 CFU/ml. The enumeration of the total fungal showed lower counts ranging from 1.0x1010 CFU/ml to 2.2x1010 CFU/ml for engine oil; 1.0x1010 CFU/ml to 1.5x1010 CFU/ml for hydraulic oil and 1.0x1010CFU/ml to 1.4x1010 CFU/ml for transition oil. The unused oil had very much lower fungal counts. The identification processes revealed the presence of Pseudomonas spp. (6.5%), Bacillus spp. (13%), Streptobacilli (21.7%), Micrococcus spp. (21.7%), Actinomyces spp. (8.6%), Nocardia spp. (4.3%), Staphylococcus spp. (10.8%), Listeria spp. (8.6%), Serratia spp. (2.1%) and Lactobacillus (2.1%). While the fungal isolates were identified as Aspergillus niger (75%), Aspergillus flavus (13.8%), Aspergillus lentulus (5.52%), Candida spp. (2.7%) and Curvularia spp. (2.7%). This result suggests that these isolated organisms from used and unused car lubricants can use oil lubricants as a source of carbon and energy, and could be explored for environmental biodegradation of hydrocarbons and bioremediation of polluted sites by these oils. Due to the medical importance of the identified organisms, care should be taken while working with the organisms, to avoid opportunistic infections.