The hexavalent chromium tolerant strain of Trichoderma pseudokoningii, isolated from chromium enr... more The hexavalent chromium tolerant strain of Trichoderma pseudokoningii, isolated from chromium enriched tannery effluent was found to produce extracellular polygalacturonase even in presence of chromium. Although there was a negative correlation between the amount of hexavalent chromium present in the cultivation medium and amount of polygalacturonase produced, moderate amount (300 U/ml) of enzymes was found to be produced even in presence of high amount of hexavalent chromium (0.80 gm/ml) in medium. The strain was found to synthesise maximum level of polygalacturonase when the culture medium was supplemented with 1.5 % (w/v) pure pectin as sole carbon source at pH 7.0 and 37 o C. The highest level of extracellular enzyme synthesis could be achieved at 72 nd hour of growth. The enzyme was stable under a wide range of pH (5.0-8.0) and up to 80 % of enzymatic activity was retained even after exposure to 90 o C for 30 minutes.
Pretreated water hyacinth was used as sole carbon source for the production of cellulase enzyme b... more Pretreated water hyacinth was used as sole carbon source for the production of cellulase enzyme by Rhizopus oryzae PR 7 MTCC 9642 in both liquid state (LSF) and solid state fermentation (SSF) that was measured by the FPase activity. To maximize the FPase production, the critical parameters like substrate concentration, cultivation temperature and pH on enzyme production were optimized using response surface methodology using Central Composite Design (CCD). The LSF was found to be better than SSF for the production of FPase. The best preferred combination for highest FPase activity from LSF was with substrate concentration 1.25%,pH 7.32 and temperature 25.25 °C. Estimated optimum conditions for FPase production from SSF was a combination of substrate concentration of 0.5%, pH 6, temperature 18°C. Under the optimized cultivation condition, the strain synthesized 123 U/ml and 48U/ml FPase from LSF and SSF respectively and the highest production was achieved within only 48 hours of cult...
Microbiologically-Synthesized Nanoparticles and Their Role in Silencing the Biofilm Signaling Cascade
Frontiers in Microbiology
The emergence of bacterial resistance to antibiotics has led to the search for alternate antimicr... more The emergence of bacterial resistance to antibiotics has led to the search for alternate antimicrobial treatment strategies. Engineered nanoparticles (NPs) for efficient penetration into a living system have become more common in the world of health and hygiene. The use of microbial enzymes/proteins as a potential reducing agent for synthesizing NPs has increased rapidly in comparison to physical and chemical methods. It is a fast, environmentally safe, and cost-effective approach. Among the biogenic sources, fungi and bacteria are preferred not only for their ability to produce a higher titer of reductase enzyme to convert the ionic forms into their nano forms, but also for their convenience in cultivating and regulating the size and morphology of the synthesized NPs, which can effectively reduce the cost for large-scale manufacturing. Effective penetration through exopolysaccharides of a biofilm matrix enables the NPs to inhibit the bacterial growth. Biofilm is the consortia of se...
A study was taken up to evaluate the role of some fermentation parameters like inoculum concentra... more A study was taken up to evaluate the role of some fermentation parameters like inoculum concentra-tion, temperature, incubation period and agitation time on ethanol production from kinnow waste and banana peels by simultaneous saccharification and fermentation using ...
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Papers by Rinarani Ray