ASSESSMENT OF INDIGENOUS MICROBIAL ENZYMES SOURCED FROM VEGETABLE OIL FACTORIES AND THEIR POTENTIALS AS ADDITIVE IN LAUNDRY DETERGENT

Abstract

Detergents are cleaning agents manufactured from synthetic chemical compounds. Detergents containing enzymes have been reported to possess more effective washing capabilities, hence the need for the study of detergent compatible enzymes. The aim of this research was to study the production conditions needed for optimal yield of lipase, protease and pectinase (enzymes) by microorganisms isolated from vegetable oil factories soil and effluents, and assessing their compatibility and potential as effective additive in the formulation of detergent. Soil and effluents samples from vegetable oil factories were collected from Ekiti and Ondo states, Nigeria. The physicochemical composition of the soils and effluents samples were also determined. Isolation of microorganisms and screening for their enzymes production abilities were carried out. The isolates that showed potential for the enzymes production were subjected to quantitative enzyme assays, and the best producers were used for further studies. Optimization for enzymes production by the copious producing isolates were also evaluated. The selected isolates were identified by PCR amplification of 16S rDNA genes. Enzymes produced under optimized conditions were purified using ammonium sulphate, dialysis and column chromatography, characterized and incorporated into formulated detergent. The soils were rich in organic matter and cations, the effluent samples possessed significant oil and grease and phosphorus content. Eight bacteria were observed as lipase producers, nine bacteria were protease producers and all five fungi were pectinase producers. Bacillus subtilis (ODK2) showed highest lipase production (2.844 U/mL), Bacillus ruris (OWO1) showed highest protease production (2.039 U/mL) and Aspergillus niger (IGB4) showed highest pectinase production (23.36 U/mL). Optimal conditions for lipase production were carbon palm oil, temperature (45 ℃), nitrogen peptone, pH (7.0), agitation speed (120 rpm), at 48 hours. Optimal conditions for protease production included carbon groundnut oil residue, temperature (45 ℃), nitrogen (casein), pH (9.0), agitation (120 rpm) at 48 hours. Optimal conditions for pectinase production were carbon pectin, temperature (30 ℃), nitrogen source (yeast extract), pH (6.0) agitation (120 rpm) at 120 hours. The purified enzymes showed decreasing enzyme activity across the purification stages. Lipase was stable at 50 ℃ (100%), protease 55°C (100%) and pectinase 55°C (100%). The enzymes were alkaline stable. The lipase, protease and pectinase (enzymes) were relatively stable in the presence of metal ions, surfactants and inhibiting agents. The purified enzymes demonstrated compatibility in the presence of the detergents with considerable cleaning performance. Enzyme function increased initially with increase in substrate concentration, time and temperature of incubation, and decreased with further increase in the processing parameters within the experimental range. This study established the ability of enzymes produced by microorganisms isolated from soil and effluents of vegetable oil factories as good additive in the production of detergent for effective dirt removal from fabrics.