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A wild type Aspergillus terreus GD13 strain, chosen after extensive screening, was optimized for lovastatin production using statistical Box-Behnken design of experiments. The interactive effect of four process parameters, i.e. lactose and soybean meal, inoculum size (spore concentration) and age of the spore culture, on the production of lovastatin was evaluated employing response surface methodology (RSM). The model highlighted the positive effect of soybean meal concentration and inoculum level for achieving maximal level of lovastatin (1342 mg/l). The optimal fermentation conditions improved the lovastatin titre by 7.0-folds when compared to the titres obtained under unoptimized conditions.

134 fungal cultures isolated from different soil samples were screened for lovastatin production. Of these, 38 isolates produced different levels of lovastatin. An Aspergillus terreus strain GD13, producing 190 mg/l of lovastatin was selected and subjected to a rational mutation-selection programme based on the resistance to lovastatin and fatty acid synthase (FAS) inhibitors, viz., iodoacetamide and N-ethylmaleimide. After three cycles of mutagenesis, a hyper-producing mutant (EM19) exhibiting 7.5-fold (1424 mg/l) higher levels of lovastatin when compared to wild type parent strain was obtained.

Ten different strains of Thermomyces lanuginosus, isolated from composting soils were found to produce phytase when grown on PSM medium. The wild type strain CM was found to produce maximum amount ofphytase (4.33 units/g DW substrate). Culturing T. lanuginosus strain CM on medium containing wheat bran and optimizing other culture conditions (carbon source, media type, nitrogen source, level of nitrogen, temperature, pH, inoculum age, inoculum level and moisture), increased the phytase yield to 13.26 units/g substrate. This culture was further subjected to UV mutagenesis for developing phytase hyperproducing mutants. The mutant (TL-7) showed 2.29-fold increase in phytase activity as compared to the parental strain. Employing Box-Behnken factor factorial design of response surface methodology resulted in optimized phytase production (32.19 units/g of substrate) by mutant TL-7. A simple two-step purification (40.75-folds) ofphytase from mutant TL-7 was achieved by anion exchange and gel filtration chromatography. The purified phytase (approximately 54 kDa) was characterized to be optimally active at pH 5.0 and temperature 70 degrees C, though the enzyme showed approximately 70% activity over a wide pH and temperature range (2.0-10.0 and 30-90 degrees C, respectively). The phytase showed broad substrate specificity with activity against sodium phytate, ADP and riboflavin phosphate. The phytase from T. lanuginosus was thermoacidstable as it showed up to 70% residual activity after exposure to 70 degrees C at pH 3.0 for 120 min. The enzyme showed Km 4.55 microM and Vmax 0.833 microM/min/mg against sodium phytate as substrate.

The paper describes shake flask culture optimization studies for the production of amylases by Thermomyces lanuginosus. The culture was found to produce maximally alpha-amylase and glucoamylase (18.4 & 11.2 units/ml), respectively when the medium contained rice flour (2% w/v) as carbon and corn steep liquor as nitrogen source with medium pH adjusted to 5.5 and incubated for 72 h under shaking conditions (150 rpm) at 50 degrees C.

A hybrid process for the fermentation of rice straw hydrolysates into ethanol was designed to simultaneously utilize cellulose and hemicellulose fractions of the agro-residue. The process involved dilute acid hydrolysis (for obtaining C-5 sugars) followed by enzymatic saccharification of cellulose enriched fraction with crude cellulase produced by mixed cultures of Trichoderma reesei Rut C-30 and Aspergillus ochraceus IMI 317911. The fermentation medium containing acid and enzymatic hydrolysate mixture of pentoses and hexoses monomers was fermented with yeast coculture of Saccharomyces cerevisiae and Pachysolen tannophilus resulting in 295.0 ml ethanol/kg of rice straw. The hybrid process resulted in an efficient utilization of both cellulosic and hemicellulosic components of the rice straw for ethanol production.

The physicochemical pretreatment of ball milled rice straw with different oxidizing agents, peracetic acid, alkali-peroxide, manganese-peroxide compounds under steaming pressure were studied. The pretreatment resulted in major changes in chemical composition of rice straw. The peroxide treated substrates were found to be most susceptible to enzymatic saccharification. A maximum saccharification (77.4%) of alkaline-peroxide treated rice straw (5%, w/v) was achieved using cellulase enzyme produced by mixed cultivation of Trichoderma reesei Rut C-30 and Aspergillus ochraceus containing 1.83 FPU, 1.63 cellobiase and xylanase 2.03 IU/ml. The hydrolysate was fermented using coculture of a temperature resistant strain of Saccharomyces cerevisiae and Pachysolen tannophilus resulting in 1.5% (w/v) ethanol. The SSF of 10.0% (w/v) H2O2-MnSO4 treated straw yielded maximum ethanol (2.9%, w/v) after 72 h at 40 degrees C. As a consequence of the well-balanced cellulase production by mixed fungal culture, the supplementation of cellobiase or xylanase was not necessary in the simultaneous saccharification and fermentation process.

Sporolactobacillus cellulosolvens (NCIMB 12173) isolated from an anaerobic digester and characterised biochemically is being reported for homofermentative lactic acid production from molasses in a batch culture. The effect of various process parameters on lactic acid production were optimized. A maximum lactic acid (24.2 g/l) and yield coefficient (0.79) was achieved using 3% (v/v) inoculum of 36 h old culture in molasses medium containing sugars (5%; w/v) supplemented with peptone (2.5 g/l) and (NH4)2SO4 (7.5 g/l), pH 6.5 at 40 degrees C after 72 h of fermentation.