title: Optimization of zofimarin production by an endophytic fungus, Xylaria sp. Acra L38.
abstract: To optimize the medium for high zofimarin production, sucrose maltose, glucose, tryptone and peptone were used in an orthogonal array design experiment, where the highest value of zofimarin produced was 25.6 μg/mL. This value was about 3 times higher than that obtained with Czapek yeast extract (CzYE) culture medium. A study with Plackett-Burman design showed that sucrose, maltose, glucose and NaNO3 were significant factors in zofimarin production. Further studies using central composite design (CCD) showed the significance of glucose and the interactions of these critical components affecting zofimarin production. Multiple regression analysis of the data yielded a poor fit as shown by the mismatch of the model with these variable factors. When a polynomial equation was applied, the maximum zofimarin production was predicted to be 201.9 μg/mL. Experimental verification yielded a much lower amount of zofimarin, at around 70 μg/mL. Reconsideration of the CCD data and repetition of some runs with high zofimarin production resulted in reproducible zofimarin yield at 79.7 μg/mL. Even though the amount was lower than the predicted value, the medium optimization study was considered to be quite successful as the yield increased to around 8 times that obtained with the original CzYE culture medium.
authors.affiliation: Department of Microbiology Faculty of Science Mahidol University RachathewiBangkok Thailand.
authors.forename: Jirapan
authors.initials: J
authors.lastname: Chaichanan
authors.affiliation: Department of Microbiology Faculty of Science Mahidol University RachathewiBangkok Thailand.
authors.forename: Suthep
authors.initials: S
authors.lastname: Wiyakrutta
authors.affiliation: Department of Biotechnology Faculty of Science Mahidol University RachathewiBangkok Thailand.
authors.forename: Thunyarat
authors.initials: T
authors.lastname: Pongtharangkul
authors.affiliation: Department of Microbiology Faculty of Science Mahidol University RachathewiBangkok Thailand.
authors.forename: Duangnate
authors.initials: D
authors.lastname: Isarangkul
authors.affiliation: Department of Microbiology Faculty of Science Mahidol University RachathewiBangkok Thailand.
authors.forename: Vithaya
authors.initials: V
authors.lastname: Meevootisom
mesh_terms: D000935:Antifungal Agents / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry*; D060026:Endophytes / Q000378:metabolism*; D007192:Indenes / Q000378:metabolism; D013098:Xylariales / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D007192:Indenes; C003329:sordarin
keywords: endophytic fungus; medium optimization; secondary metabolite; statistical methods; zofimarin