Hexavalent Chromium (Cr+6) induced several toxicological changes in the developing rice (Oryza sativa L.) seedlings as showed from present in vitro hydroponic study. Growth parameters, physiological and biochemical alterations in rice were studied in response to the application of toxic concentration of Cr+6 with addition of chelating agents. Rice seedlings growing in nutrient solutions supplemented with Cr+6 (100μM) showed noticeable decrease in root and shoot length, fresh and dry matter; whereas addition of chelating agents like EDTA, DTPA and EDDHA with Cr+6 at 10 μM stimulates the growth. Chlorophyll and carotenoid biosynthesis was also declined with the treatment of Cr+6 (100μM), but application of Cr+6-EDTA (10μM) amplified the pigment biosynthesis. Rice seedlings treated with Cr+6(100μM) showed increased proline content and high Cr accumulation in root whereas treatments of Cr+6-DTPA (10μM) enhanced the shoot Cr bioaccumulation as compared to other treatments. Supplementation of Cr+6-EDTA (10μM) showed increased phytoextraction of Cr in roots of rice seedlings. Transportation index (Ti) of seedlings grown in Cr+6 (10μM) and Cr+6- DTPA (10μM) was found more in comparison to others. The variations in the total accumulation rate (TAR) of Cr of different seedlings were negligible.

The objective of this study is to investigate the optimal parameter levels for removal of nitrates from wastewater using Pseudomonas stutzeri in a fluidized bed bioreactor by Taguchi method and validating the predicted values. In this study the influence of airflow rate, temperature, carbon source, PP beads (Poly Propylene) and pH at different levels was investigated was made using Taguchi’s L16(4)5 orthogonal array technique. The nitrate removal efficiency after optimization is more than 96% with airflow rate at level 2 (A2), temperature at level 3(B3), carbon source at level 4(C4), PP beads at level 2(D2) and pH at level 2(E2). The analysis of variance (ANOVA) test is used to determine the percent contribution of each parameter and found that airflow rate contribution is the highest and temperature provides the least contribution.

In the present study, 50 microbial strains were isolated from the soil samples from different regions of Andhra Pradesh. Among the isolates hyper producing strain namely, Bacillus Clausii was selected for alkaline protease production. The protease production efficiency of the organisms was measured with different environmental and nutritional parameters. The optimum fermentation conditions of production were temperature 40°C, pH 8 and time 32H. Fructose, peptone and Copper sulphate as good nutritional sources for producing higher yields of the enzyme.

Nitrate is a major pollutant present in effluent wastewater from nitrogenous fertilizer, explosives, paper mills, pulp mills, and also from municipal waste. Nitrate is harmful to both mankind and animal and also to the environment. The World Health Organization has set a limit of 10 mg/L NO3- for human consumption and 100 mg/l NO3- for animals. Water above these limits requires denitrification. Nitrates causes cancer, blue-bay syndrome, hypertension and thyroid hypertrophy. Experimentation on biological denitrification was carried out in a fluidized bed bio-reactor using synthetic wastewater with polypropylene beads as supporting media for the growth of microorganism. Synthetic wastewater is taken into the reactor for biological treatment and air was fed from bottom with solids being fluidized at the top due to low density. Experiments were performed for water of different initial nitrate concentrations with Pseudomonas stutzeri microorganism by varying the parameters like airflow rate, temperature, carbon source, poly propylene beads and pH in the range 2 lpm to 3.5 lpm, 20°C to 35°C, 70 mg/L to 85 mg/L, 5 mg/L to 25 mg/L and 6 to 8 respectively. The optimum parameters at which maximum denitrification is noticed are found to be 2.5 lpm (air flow rate), 30°C (temperature), 85 mg/L (carbon source), 15 mg/L (polypropylene beads) and 7 (pH). More than 95% removal of nitrates is noticed from the experimental work. The objective of the study is to investigate the effect of operating parameters like airflow rate, temperature, carbon source, polypropylene beads and pH.

The work involves an experimental study on the effect of initial yeast extract concentration on microbial production of xylitol from xylose using Candida Parapsilosis NCIM-3323 and the optimum values have been established. The initial yeast extract concentration was varied in the range of 3-8 g/l at a temperature of 30 oC, pH of 3.5 and initial xylose concentration of 60 g/l. It is observed that maximum production of xylitol is obtained for an initial yeast extract concentration of 4 g/l. It is seen that maximum xylitol concentration of 17.96 g/l, maximum xylitol yield of 0.299 g/g, maximum xylitol volumetric productivity of 0.748 g/g.h and maximum specific productivity of 0.0125 g/g.h were obtained for an initial extract concentration of 4 g/l.