Renewable biodiesels are needed as an alternative to petroleum-derived transport fuels, which contribute to global warming and are of limited availability. Algae biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuels. This study introduces an integrated method for the production of biodiesel from Chara vulgaris algae collected from the coastal region of Bangladesh. The Box–Behnken design based on response surface methods (RSM) used as the statistical tool to optimize three variables for predicting the best performing conditions (calorific value and yield) of algae biodiesel. The three parameters for production condition were chloroform (X1), sodium chloride concentration (X2) and temperature (X3). Optimal conditions were estimated by the aid of statistical regression analysis and surface plot chart. The optimal condition of biodiesel production parameter for 12 g of dry algae biomass was observed to be 198 ml chloroform with 0.75 % sodium chloride at 65 °C temperature, where the calorific value of biodiesel is 9255.106 kcal/kg and yield 3.6 ml.

Biodiesel is an alkyl ester of long chain fatty acids and considered as an alternative to lower the appalling consequence of fuel on the environment. It is produced by transesterification of a fat or oil with a short chain primary alcohol like methanol and alkali like sodium hydroxide (NaOH). Palm oil (Elaeis guineensis) was used as source to produce biodiesel and Box Behnken experimental design was applied to see the effect of various process parameters, i.e. methanol quantity, alkali concentration and temperature for the optimization of calorific value of biodiesel. Response surface plots and contour plot were created in order to perceive the optimum condition. Though, all the three variables significantly affected the calorific value of the palm biodiesel, but it was found that methanol was more effective variable than alkali concentration and temperature. It was observed that 12.5 ml methanol/50 ml oil and 0.4 gm NaOH/50 ml oil and 55°C temperature were optimum condition, where the calorific value of palm biodiesel is 9297.206 kcal/kg.

In modern era, the use of plastic product in different sector of industry is increasing day by day. The extensive use of plastic-a synthetic organic polymer derived from natural fossil fuel and persists in the nature for a very long time due to the lack of degradability, engenders negative impact on environment. Their disperse disposal in land and water arouses threats for human, wildlife and aqua life. Pervasive researches have been carried out on plastic degradation to find solution to overcome these environmental hazards allied with plastic waste. Biodegradation emerges as one of the promising solution to manage the plastic waste which could not be recycled. In biodegradation process microorganism and their enzymes are applied to degrade the synthetic and bio-based plastics. This review encompasses the current progress on biodegradation of various plastic polymers by microorganisms and analytical technique to determine the extent of degradation.