Abstract

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Wastewater samples were collected from cocoa processing plant effluent in Ondo, Nigeria. Lipase-producing bacteria were isolated and screened from the effluent. Four bacterial isolates showed lipolytic activities and were assessed both qualitatively (agar plate cultures) using tributyrin agar and quantitatively (liquid cultures) using olive oil as sole carbon and energy source. The bacterium with the highest lipase activity was selected, identified by biochemical methods and using molecular techniques. The optimization of the production medium for maximum production and lipase activity were carried out. Lipase activity was assayed by a spectrophotometric method. The absorbance of p-Nitrophenol released was measured at 410 nm. The 16S rRNA gene sequencing confirmed the bacteria with the highest lipase activity to be Brevundimonas diminuta. Maximum enzyme production was obtained when the medium was incubated for 72 h (35.85± 0.5 U/ml) at temperature of 35°C and maintained at pH 7.5. Olive oil (with 30.00 ± 4.09 U/ml) and peptone (with 47.33 ± 1.26 U/ml) were found to be the most suitable substrate for maximum enzyme production. The organism also utilized the effluent (with 4.78 ± 0.16 U/ml) as carbon source. The study concluded that cocoa processing plant effluent contain substrate that makes it a renewable source for the production of microbial lipase.

Keywords: Brevundimonas dimunita; Cocoa; Effluent; Lipase