Govindasamy Sharmila

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.

Carboxymethylation of pectin: Optimization, characterization and in-vitro drug release studies

The sequential optimization of carboxymethylation of pectin by Plackett-Burman (PB) design and response surface methodology (RSM) was reported in this study. PB design was employed to screen the six process variables (ethanol concentration, liquid-polymer ratio, NaOH concentration, CAA concentration, temperature and time). Central composite design (CCD) was used to study the interaction effects of ethanol concentration, NaOH concentration, CAA concentration and time on degree of substitution (DS) in carboxymethylated pectin (CMP). Maximum DS value of 0.496 was predicted at ethanol concentration (80%), NaOH concentration (38%), CAA concentration (8.5%) and time (60 min). The synthesized CMP was characterized by FT-IR, XRD, TGA and viscometer. Results of FTIR, XRD and TGA confirmed the modification made in the pectin polymer and highly methylated. Faster release of 5-FU drug was observed with CMP-chitosan nanoparticles as compared to pectin-chitosan nanoparticles and the drug release followed zero order kinetics model.