Botryosphaeria spp. as Producers of Laccase When Cultivated on Vegetable Oils as Sole Carbon Source: Optimizing Laccase Production by Botryosphaeria rhodina MAMB-05 on Soybean Oil

Abstract

Eight vegetable oils and glycerol were examined as sole carbon source to screen nine isolates of Botryosphaeria spp. Among these, B. rhodina MAMB-05 produced highest laccase titres on all carbon sources evaluated followed by B. rhodina MMLR isolated (from orange, Citrus sp.). The influence of inorganic nitrogen (NH₄Cl, NaNO₃, (NH₄)₂SO₄, and NH₄NO₃), organic nitrogen (yeast extract (YE), urea, peptone, and corn steep liquor) sources, inorganic phosphate (KH₂PO₄, Na₂HPO₄, NaH₂PO₄, K₂HPO₄), as well as increasing concentrations of copper (from zero to 100 µg mL^-1), as nutritional requirements for enhancing laccase production by B. rhodina MAMB-05 were also evaluated. Soybean oil was the only carbon source in a central composite factorialdesign (2³) to optimize laccase production with the selected variables NaNO₃, KH₂PO₄ and copper (CuSO₄.5H₂O), using the response surface methodology. The optimal conditions obtained were NaNO₃ (100 g L^-1), KH₂PO₄ (125 g L^-1) and 50 µg mL^-1 of CuSO₄.5H₂O. The specific laccase activity obtained (2.95 U mg^-1) in the validation experiments using the optimal condition for laccase production by B. rhodina MAMB-05 was in agreement with the predicted value (3.07 U mg^-1), and demonstrated the fitness of the proposed model.

DOI: http://dx.doi.org/10.17807/orbital.v10i7.1206