K. Krishna Prasad

Treatment of simulated Reactive Yellow 22 (Azo) dye effluents using Spirogyra species

The potential of commonly available green algae belonging to Spirogyra species was investigated as viable biomaterials for biological treatment of simulated synthetic azo dye (Reactive Yellow 22) effluents. The results obtained from the batch experiments revealed the ability of the algal species in removing the dye colour and was dependent both on the dye concentration and algal biomass. Maximum dye colour removal was observed on the third day for all the system conditions. Monitoring of ORP values helped to understand the overlying biochemical mechanism of algal-dye system. Based upon the results, the dye-algal treatment mechanism was attributed to biosorption (sorption of dye molecules over the surface of algal cells), bioconversion (diffusion of dye molecules into the algal cells and subsequent conversion) and biocoagulation (coagulation of dye molecules present in the aqueous phase onto the biopolymers released as metabolic intermediates during metabolic conversion of dye and subsequent settlement).

Xylitol production by Candida sp.: parameter optimization using Taguchi approach

Abstract Xylitol production parameter optimization using a newly isolated Candida sp. was performed using Test plan L18, available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi approach. Optimal levels of physical parameters and key media components namely temperature, pH, agitation, inoculum size, corn steep liquor (CSL), xylose, yeast extract and KH 2 PO 4 were determined. Among the physical parameters, temperature and agitation contribute higher influence. Media components CSL, xylose concentration and KH 2 PO 4 play an important role in the conversion of xylose to xylitol. The yield of xylitol under these optimal conditions was 78.9%.

Microbial degradation of pyridine using Pseudomonas sp. and isolation of plasmid responsible for degradation

Pseudomonas (PI2) capable of degrading pyridine was isolated from the mixed population of the activated sludge unit which was being used for treating complex effluents, the strain was characterized. Aerobic degradation of pyridine was studied with the isolated strain and the growth parameters were evaluated. Pyridine degradation was further conformed by chromatography (HPLC) analysis. The process parameters like biomass growth and dissolved oxygen consumption were monitored during pyridine degradation. In order to conform with the plasmid capability to degrade pyridine, the requisite plasmid was isolated and transferred to DH 5alpha Escherichia coli. The subsequent biodegradation studies revealed the ability of the transformed plasmid capability to degrade the pyridine.