AMB Volume 42, Issue 1, 2026 Pages 76-87 https://doi.org/10.59393/amb26420109
Production of Extracellular Surfactants as Biotechnologically Versatile Products by Fungal Isolates of Palm Oil Mill Effluent
Dowe E., Ejovwokeoghene E.F., Ayobola E.D., Onoriadjeren W.O.
This study employed untreated Palm oil mill effluent (POME) as both microbial source and fermentation substrate for the production of extracellular biosurfactant. POME samples were collected from an automated mill (NIFOR) and a semi-automated local mill (Iguiye community) in Edo State, Nigeria. Physicochemical analysis of the POME samples showed acidic pH (3.8–5.1), elevated biochemical oxygen demand (22 300–36 600 mg/L), and high oil and grease content (3 439–7 104 mg/L), indicative of significant pollution. Fungal enumeration revealed total counts ranging from 1.43 ± 1.12 × 106 to 6.51 ± 1.88 × 106 cfu/ mL at NIFOR and 2.26 ± 0.93 × 106 to 8.70 ± 1.58 × 106 cfu/mL at Iguiye. Isolation and characterization using standard microbiological techniques and 28S rRNA (D1/D2) gene sequencing yielded 126 isolates across nine genera. Penicillium oxalicum, Aspergillus flavus, Aspergillus niger, Geotrichum candidum, Candida utilis, and Rhodotorula glutinis produced extracellular biosurfactants under submerged fermentation in POME-augmented mineral salt medium. Biosurfactant activity was confirmed through drop-collapse, oil displacement, emulsification index (E24), hemolytic activity, and surface tension reduction, with purified products from G. candidum and C. utilis reducing surface tension to <15 mN/m and exhibiting high emulsification. Activities were significantly different (P < 0.05) from the positive control (Tween-80). The findings highlight a sustainable strategy for valorizing agro-industrial waste while producing biotechnologically versatile fungal biosurfactants suitable for various applications.
Keywords: biosurfactant, palm oil mill effluent, fungi, waste valorization, surface tension
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