Response surface methodology was employed to optimize culture medium for production of lipase with Rhodotorula sp. MTCC 8737. In the first step, a Plackett-Burman design was used to evaluate the effects of different inducers qualitatively. Of all the seven inducers tested, soybean oil showed significant influence on the lipase production. Further, response surface studies were conducted to quantitatively optimize by considering linear, interactive, and quadratic effects of test variables. A novel approach was proposed to optimize the lipase production system by optimizing the responses in terms of yield kinetics rather than optimizing the direct responses like lipase titer and biomass growth. The coefficient of determination (R(2)) calculated for Y (P/S) (0.769), Y (P/X) (0.799), and Y (X/S) (0.847) indicated that the statistical model could explain 76.9%, 79.99%, and 84.7% of variability in the response.

Introduction: Fruit polysaccharides, essential health factors in foods, are widely present in edible fruits. Several methods for isolation of polysaccharide are available. Microwave Assisted Extraction (MAE) method is extensively used for separation of polysaccharides. Only little information is available about Psidium guajava L. Fruit Polysaccharide (PFP) and its extraction methods. Objective: In this study, two extraction methods of polysaccharides in Psidium guajava L. fruit were compared and the best method was ascertained. Methods: Psidium guajava L. polysaccharides were extracted using water extraction with conventional heating and microwave assisted extraction method. The factors that influenced water extraction with conventional heating included temperature, water to plant material ratio, extraction time and solvent to liquid ratio. The factors that influenced MAE of polysaccharides extraction included microwave power, irradiation time and solvent to liquid ratio. Yield is considered as the independent variable in both the methods. Results: By the result of the single factorial method and orthogonal experiments, the optimal extracting conditions were selected and then the best extraction method was ascertained. The optimum extraction conditions of water extraction with conventional heating include , temperature 90

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