No abstract

No abstract

No abstract

No abstract

No abstract

Amylases from Rhizopus oryzae and Rhizopus microsporus var. oligosporus were obtained using agro-industrial wastes as substrates in submerged batch cultures. The enzymatic complex was partially characterised for use in the production of glucose syrup. Type II wheat flour proved better than cassava bagasse as sole carbon source for amylase production. The optimum fermentation condition for both microorganisms was 96 hours at 30°C and the amylase thus produced was used for starch hydrolysis. The product of the enzymatic hydrolysis indicated that the enzyme obtained was glucoamylase, only glucose as final product was attained for both microorganisms. R. oligosporus was of greater interest than R. oryzae for amylase production, taking into account enzyme activity, cultivation time, thermal stability and pH range. Glucose syrup was produced using concentrated enzyme and 100 g L−1 starch in a 4 hours reaction at 50°C. The bioprocess studied can contribute to fungus glucoamylase production and application.

This study provides a comparison of fermentation conditions for the production lipases by Fusarium sp. (Gibberella fujikuroi complex) isolate FCLA-MA-41 in submerged (SmF) and solid-state fermentation (SSF) using agro-industrial residues. To assess SmF, a univariate study of seven carbon sources (crambe, corn, linseed, olive, palm (dendê), soybean oils and chicken fat) and four nitrogen sources (ammonium sulfate, sodium nitrate, urea, yeast extract) was performed. The relationship among the concentrations of carbon and nitrogen sources, Triton X-100 and yeast extract was studied using a Central Composite Design (CCD). To assess SSF, different residues (sugarcane bagasse) and oil-seed meals (castorbean, corn, crambe, soybean) with additional supplements added (minimum salts, seed oils) were examined. Based on the CCD matrix, a medium containing crambe oil (17.5 mL/L), Triton X-100 (5 g/L), ammonium sulfate (5 g/L) and yeast extract (1 g/L) was proposed, resulting in a lipase titer of 3.0 AE 0.25 U/mL. The cost/production relationship was 7.73% less expensive than SmF with corn oil. SSF produced a maximum lipase titer of 5.0 AE 0.25 U/gds on crambe meal moistened with phosphate buffer. The best cost/enzyme activity estimate was for SSF with crambe meal as substrate in only distilled water (87.27% less expensive than SmF).

The effects of soybean and castorbean meals were evaluated separately, and in combinations at different ratios, as substrates for lipase production by Botryosphaeria ribis EC-01 in submerged fermentation using only distilled water. The addition of glycerol analytical grade (AG) and glycerol crude (CG) to soybean and castorbean meals separately and in combination, were also examined for lipase production. Glycerol-AG increased enzyme production, whereas glycerol-CG decreased it. A 2(4) factorial design was developed to determine the best concentrations of soybean meal, castorbean meal, glycerol-AG, and KH2PO4 to optimize lipase production by B. ribis EC-01. Soybean meal and glycerol-AG had a significant effect on lipase production, whereas castorbean meal did not. A second treatment (2(2) factorial design central composite) was developed, and optimal lipase production (4,820 U/g of dry solids content (ds)) was obtained when B. ribis EC-01 was grown on 0.5 % (w/v) soybean meal and 5.2 % (v/v) glycerol in distilled water, which was in agreement with the predicted value (4,892 U/g ds) calculated by the model. The unitary cost of lipase production determined under the optimized conditions developed ranged from US$0.42 to 0.44 based on nutrient costs. The fungal lipase was immobilized onto Celite and showed high thermal stability and was used for transesterification of soybean oil in methanol (1:3) resulting in 36 % of fatty acyl alkyl ester content. The apparent K m and V max were determined and were 1.86 mM and 14.29 μmol min(-1) mg(-1), respectively.