Study of growth kinetics of high lipid microalgae in local environment

Abstract

Clean energy supply has always been a challenge confronting humanity. Wind energy, geothermal energy, solar energy and biofuel are among the most important options proposed during the last century. Biofuel has many unique capabilities that drew attention more than other sources. There are several criteria that make microalgae a potential candidate for biodiesel production. For example- they can be cultivated on non-arable lands using non- potable water, all the year round. Moreover, several species have the ability to accumulate high amount of lipid which can further be increased by modifying culture conditions with the biotechnology techniques. Microalgae are unicellular, photosynthetic microorganisms, they have minimal nutrient requirements and are being used as source materials for a variety of products such as protein rich nutritional supplements, pharmaceutical chemicals and pigments (used in food and cosmetics). The strain Chlorella vulgaris, has shown a great potential as a source of oil and also in helping in wastewater treatment. Challenges in the process of producing biodiesel from microalgae include effective techniques to grow microalgae and harvest the grown microalgae, extraction of the algal oil and its trans-esterification to biodiesel. The goal of the present study is to study the behavior of the selected microalgae in the local environment. Microorganisms behave differently in different environments. The culture media which worked in one environment might not produce satisfactory result in another environment. Hence, it is important to find a suitable culture media in the local environment. This study has been crucial to develop an economical process to produce biodiesel from microalgae. The production of microalgae Chlorella vulgaris in four different media was investigated in batch culture. The results were analyzed to find the most suitable media. The best response was recorded for modified CH media. In this media, an exponential phase with duration of 15 days was recorded, where the concentration of the biomass at the end of the period was 2.84 g/L. Moreover, the culture in this media was recorded to have the highest specific growth rate (0.136 d-1), lowest doubling time (53.28 hours) and maximum volumetric biomass yield (0.106 gL-1d-1). The study also showed that Bold’s Basal medium which is the most frequently used medium for culturing Chlorella vulgaris did not respond accordingly in our local environment.