The extensive efforts to screen thermophilic fungi and bacteria, isolated from various environmental samples, have resulted in the selection of Thermomucor indicae-seudaticae, Geobacillus thermoleovorans NP33 and G. thermoleovorans NP54 for the production of glucoamylase, amylopullulanase and alpha-amylase, respectively. Submerged and solid-state fermentation processes were optimized for maximizing the secretion of glucoamylase by T. indicae-seudaticae. The production of amylopullulanase and alpha-amylase by NP33 and NP54 in submerged fermentation was also optimized. Glucoamylase was optimally active at pH 7.0 and 60 degrees C and was shown to saccharify soluble as well as raw starches. Amylopullulanase and alpha-amylase exhibited optima at pH 7.0 and 100 degrees C and saccharified starch efficiently. Differential inhibition and action on mixed substrates clearly suggested that there are two separate active sites for alpha-amylase and pullulanase activities of amylopullulanase. Both alpha-amylase and amylopullulanase are high maltose-forming and Ca(2+)-independent. These amylolytic enzymes have been shown to be useful in starch saccharification alone and in combination.

The secretion of Ca2+-independent hyperthermostable alpha-amylase was enhanced in the presence of certain anionic and non-ionic detergents in the medium. Furthermore, the surfactants stabilized the enzyme during preservation at 4 degrees C. The use of this enzyme in starch hydrolysis eliminates the addition of Ca2+ in starch liquefaction and its subsequent removal by ion exchange from sugar syrups.

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Synthetic dyes are released into the environment from textile industrial effluents. The discharge of this colored wastewater into rivers and lakes leads to a reduction in sunlight penetration in natural water bodies, which, in turn, decreases both photosynthetic activity and dissolved oxygen concentration and is toxic to living beings. Bacterial isolates are optimized for growth and biomass production before using them for decolorizing dye effluent. The bacterial isolates Bacillus sp. 1 and Bacillus sp. 2 were employed at different percentages by volume with standard nutrient concentration. Of these bacterial isolates Bacillus sp. 2 recorded maximum color reduction. The pH and electrical conductivity (EC) were reduced in the decolorized effluent, and a reduction in biologic oxygen demand, chemical oxygen demand, total suspended solids, and total dissolved solids (TDS) were also observed.

Aim: Statistical optimization for maximum production of a hyperthermostable, Ca 2+ -independent and high maltose-forming a-amylase by Geobacillus thermoleovorans. Methods and Results: G. thermoleovorans was cultivated in 250 ml flasks containing 50 ml of chemically defined glucose-arginine medium (g l )1 : glucose 20; arginine 1AE2; riboflavin 150 lg ml )1 ; MgSO 4 . 7H 2 O 0AE2; NaCl 1AE0; pH 7AE0). The medium was inoculated with 5 h-old bacterial inoculum (1AE8 · 10 8 CFU ml )1 ), and incubated in an incubator shaker at 70°C for 12 h at 200 rev min )1 . The fermentation variables optimized by Ôone variable at a timeÕ approach were further optimized by response surface methodology (RSM). The statistical model was obtained using central composite design (CCD) with three variables: glucose, riboflavin and inoculum density. An over all 24 and 70% increase in enzyme production was attained in shake flasks and fermenter because of optimization by RSM, respectively. A good coverage of interactions could also be explained by RSM. The end products of the action of a-amylase on starch were maltose (62%), maltotriose (31%) and malto-oligosaccharides (7%). Conclusions: RSM allowed optimization of medium components and cultural parameters for attaining high yields of a-amylase, and further, a good coverage of interactions could be explained. The yield of maltose was higher than maltotriose and malto-oligosaccharides in the starch hydrolysate. Significance and Impact of the Study: By applying RSM, critical fermentation variables were optimized rapidly. The starch hydrolysate contained a high proportion of maltose, and therefore, the enzyme can find application in starch saccharification process for the manufacture of high maltose syrups. The use of this enzyme in starch saccharification eliminates the addition of Ca 2+ .