The purpose of the present investigation is to enhance production of the biomedically important enzyme, lipase, by subjecting the indigenous lipase producing fungal strain Aspergillus japonicus MTCC 1975 to strain improvement and random mutagenesis (UV irradiation, HNO 2 and N-methyl-N'nitro-N-nitroso guanidine). The isolation of mutants and the lipolytic activity of selected mutants were described. The best UV selectant (AUV 3) showed 127% higher lipase activity than the parent strain. The lipase yield of the best HNO 2 mutant (AHN 3) was 139% higher than UV mutant (AUV 3) and 177% higher than the parent strain. Also, the lipase yield of the best NTG mutant (ANT 4) was 156% higher lipase activity than the HNO 2 mutant (AHN 3) and 217% higher than the UV mutant (AUV 3) and 276% higher lipase activity than the parent strain. The results indicated that UV, HNO 2 and NTG treatment were effective physical and chemical mutagenic agents for strain improvement of Aspergillus japonicus for enhanced lipase productivity.

Doehlert experimental design (DD) was applied for the optimization of medium constituents for L-asparaginase production by Yarrowia lipolytica NCIM 3472 in solid state fermentation (SSF) using palm kernel cake as the substrate. From the results of preliminary experimental runs, the three variables (glucose, moisture content, L-asparagine) have been identified as the potential variables for the production of L-asparaginase. Fifteen experimental runs designed by DD are carried out and the process response is modeled using a polynomial equation as function of these parameters. The proposed quadratic model for DD fitted very well to the experimental data that it could be used to navigate the design space according to analysis of variance results. The experimental values were in good agreement with predicted values and the correlation coefficient was found to be 0.9988. The optimal set of conditions for maximum L-asparaginase activity was as follows: moisture content of the substrate: 54.8622 (%), glucose concentration: 11.9241 (%w/w) and L-asparagine concentration: 1.0758 (%w/w). L-asparaginase activity at these optimum conditions was 39.8623 U/gds. STATISTICA 6.0 was used for implementing Doehlert experimental design.

Application of statistical experimental designs for optimization of fermentation parameters to enhance ethanol production, which is an economical and renewable energy source using Saccharomyces cerevisiae NCIM 3090 from palmyra jaggery, was studied in a batch fermentor. Using Plackett-Burman design, impeller speed, concentrations of CoCl2 and KH2PO4 were identified as significant variables, which highly influenced ethanol production, and these variables were further optimized using a central composite design (CCD). The ethanol production was adequately approximated with a full quadratic equation obtained from three factors and five levels of CCD. Maximum ethanol concentration of 132.56 g/l (16.8% [v/v]) was obtained for an impeller speed of 247.179 ( approximately 250) rev/min, CoCl2 of 0.263 g/l and KH2PO4 of 2.39 g/l. A second-order polynomial regression model was fitted and was found adequate with R 2 of 0.8952. This combined statistical approach enables rapid identification and investigation of significant parameters for improving the ethanol production and could be very useful in optimizing processes.

A rapid and sensitive RP-HPLC method with UV detection (242 nm) for routine analysis of famciclovir in pharmaceutical formulations was developed. Chromatography was performed with mobile phase containing a mixture of methanol and phosphate buffer (50:50,v/v) with flow rate 1.0 mL min−1. Quantitation was accomplished with internal standard method. The procedure was validated for linearity (correlation coefficient =0.9999), accuracy, robustness and intermediate precision. Experimental design was used for validation of robustness and intermediate precision. To test robustness, three factors were considered; percentage v/v of methanol in mobile phase, flow rate and pH; flow rate, the percentage of organic modifier and pH have considerable important effect on the response. For intermediate precision measure the variables considered were: analyst, equipment and number of days. The RSD value (0.86%,n=24) indicated an acceptable precision of the analytical method. The proposed method was simple, sensitive, precise, accurate and quick and useful for routine quality control.

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