Chandrasekaran Muthukumaran

Application of response surface methodology to the optimization of amylase production by Aspergillus oryzae MTCC 1847

This research paper mainly focused on developing a media by optimizing parameters like sweet potato concentration, sodium nitrate concentration, pH, temperature for the maximum production of amylase by Aspergillus oryzae MTCC 1847. Optimization of the medium components such as sweet potato (carbon source), sodium nitrate (nitrogen source) and parameters like pH and temperature were studied for the amylase production by using response surface methodology (RSM) based central composite design (CCD). By using the surface plots and response optimizer of MINITAB 14 Software, the maximum enzyme activity of 0.893 IU/ml was predicted when sweet potato concentration was 2.01%, sodium nitrate 0.6%, pH 7.2 and temperature 25°C. Key words: Sweet potato, Aspergillus oryzae , response surface methodology, central composite design

Bioremediation of Volatile Organic Compounds in Biofilters

In India, 12 lakhs deaths per annum take place due to air pollution according to a report by Greenpeace organization. Volatile organic compounds are major air pollutants which are released into the environment through mobile sources, stationary sources, area sources, and natural sources. Stationary sources such as petrochemical and pharmaceutical industries release VOCs like toluene which is known to cause several health hazards including lung cancer. In addition to it, VOCs pollute air, soil, and water which are a growing environmental concern. Based on the concentration level of the VOCs, several removal techniques have been employed to combat VOCs. Non-biological methods such as ozonation, absorption, adsorption, incineration, catalytic oxidation, condensation, membrane separation are being employed. Several biological methods ranging from biotrickling filters to biofilters have been demonstrated, and they are found to be economical. The biofilters are simple to construct, easy to operate, and cost effective. Major advantage of this method is the pollutant is converted into biodegradable waste which can decompose within a moderate time frame, thus producing no secondary pollutants. In this chapter, biofilters, microorganisms, biofilter preparation and reaction mechanism are discussed. More emphasis was given on operation, processes, conditions, and stability of biofilters. The recent advancements in biofilters including application of foam for enhanced separation and the limitations of the biofiltration methods are also discussed. Future scope and summary of the chapter are given at the end of the chapter to provide an insight into biofilters research.

Genetically Modified Organisms and Its Impact on the Enhancement of Bioremediation

Bioremediation is a process of degrading the environmental contaminants, that are introduced accidentally or purposely which cause hazardous effect on earth and harm the normal life process. The conversion of these contaminants into less toxic forms is the goal of bioremediation process that can be achieved by the use of microorganisms. The bioremediation approaches have more advantages when compared with the traditional methods, as it can be directly implemented at the targeted contaminant site. Even though some bacteria and fungus were employed to decompose the chemical compounds, but they have only limited ratio to metabolize the hydrocarbons on their own. The genetically modified organisms are applied nowadays in bioremediation process for effective removal of contaminants, where the indigenous microbes cannot degrade. Genetically modified microorganisms (GMOs) play an important role in remediating the industrial waste, reduce the toxicity of some hazardous compounds, and also help in removal of pollution by hydrocarbons and petrol discharges. A variety of molecular tools such as molecular cloning, horizontal transfer of DNA in bacteria, electroporation, protoplast transformation, biolistic transformation, conjugation and transformation of competent cells are available for the successful construction of GMOs. Transfer of gene into the bacteria makes it as a novel strain, for eliminating the hydrocarbon contaminants from the environment in minimal time. Similarly, removal of compounds such as xylene, toluene, octane, naphthalene and salicylate is coded on bacterial plasmids for successful degradation of the environment. This chapter represents the applications of genetically modified organisms in bioremediation processes, molecular tools used for construction of GMOs, pros and cons, ethical issues and laws governing the application of GMOs.