The current study aimed to the production and partial purification of a cold-active lipase by som fungi isolated from the olive oil processing wastes in Al-Gabal Al-Gharby, Libya. 31 fungal species from 12 genera were isolated. F. solani was the most prevalent comprising 94% of total Fusarium and 28.7% of total fungi, 102 fungal isolates were tested for their lipolytic activity on lipase production agar medium at 10 and 20°C. The most active isolates were Alternaria (2 isolates), Fusarium, and Penicillium (1isolate for each one). Molecular identification of the most active four isolates was carried out by their sequencing (ITS). The four powerful fungal strains' production of cold-active lipase was maximized by optimizing some nutritional and environmental factors. F. solani AUMC 16063 was able to produce the maximum amount of lipase activity (46.66U/mL/min) with specific activity (202.8U/mg), utilizing ammonium sulphate as a nitrogen source after 8 days of incubation at pH 3.0 and 15°C. However, at same condition after 6 days when yeast extract was employed as a nitrogen source, the generated cold-active lipase displayed the highest specific activity of (1550U/mg) and lipase activity (36.74U/ml/min). This is the first study in which the production, partial purification, maximized and characterization of a cold-active lipase enzyme by Fusarium solani. Keywords: cold active enzymes, Lipase, Fusarium solani, lipolytic activity, specific activity. 

Abstract: The current study was aimed for isolation, identification and preservation of mycobiota associated with the olive oil processing wastes (Fatura) collected from different cities in Al-Gabal Al-Gharby, Libya, screening the cold-active lipolytic activity of the isolated fungi and selection of the highest cold-active lipase producers. 31 fungal species belong to 12 genera were isolated from these samples with total CFUs of 29560. Fusarium was the most common genus at total CFUs of 9020 and comprising 30.51% from all fungi, followed by Aspergillus, that recorded 25.44% from all fungi. Penicillium was ranked third, nine different species were present. A total of 100% of samples were found to have CFUs of 5140 and 17.4% of all fungi. On lipase production agar medium at two temperatures, 10 and 20°C, 102 fungal isolates from 31 species were tested for their lipolytic activity. The majority of fungi could produce lipase activity at 20°C, where 98 out of 102 isolates the highest lipase producers was higher at 10°C (25) than at 20°C (16). The most active isolates were Alternaria, Fusarium, and Penicillium. Molecular identification of the most active four isolates was carried out by sequencing their internal transcribed spacer region (ITS).

 Keyword: Olive oil, cold active enzymes, Lipase, fungi, lipolytic activity, Fatura.