251 © Springer International Publishing AG 2017 M. Kumar, P. Ralph (eds.), Systems Biology of Marine Ecosystems, DOI 10.1007/978-3-319-62094-7_13 Chapter 13 Oxidative Stress-Induced Bioprospecting of Microalgae Kaumeel Chokshi, Imran Pancha, Arup Ghosh, and Sandhya Mishra Abstract Microalgae are sunlight-driven cell factories found in diverse marine and freshwater environments. With simple growth requirements (light, CO 2 , N, P and K), microalgae produce various valuable products like carotenoids, antioxidants, fatty acids, enzymes, polymers, peptides, toxins and sterols. Their photosynthetic mechanism is similar to plants, but due to their simple cellular structure and sub- mergence in an aqueous environment, in most cases, they have an efficient access to water, CO 2 and other nutrients. In addition, their growth is faster and photosynthetic efficiency is higher compared to terrestrial crop plants. Their shorter generation time allows production of lipids and carbohydrates in large amounts over short peri- ods of time, which can be easily converted into biofuels. Due to these reasons, microalgae are considered as an alternative renewable feedstock for biofuel produc- tion. In any organism, fluctuating environmental conditions trigger a series of physi- ological processes and generation of reactive oxygen species (ROS) which are highly reactive and damage proteins, lipids, carbohydrates and DNA, ultimately resulting into cellular toxicity. Stress-induced ROS accumulation is counteracted by cellular enzymatic and non-enzymatic antioxidants. Excessive ROS damage the ability of the cells to readily detoxify the reactive intermediates or to repair the resulting damage, ultimately leading to oxidative stress conditions. Recent studies suggest that oxidative stress is a mediator for increased accumulation of lipid and various bioactive metabolites in microalgae. This chapter provides comprehensive K. Chokshi • S. Mishra (*) Discipline of Salt and Marine Chemicals, CSIR—Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, India Academy of Scientific and Innovative Research (AcSIR), CSIR—Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, India e-mail: smishra@csmcri.res.in I. Pancha Discipline of Salt and Marine Chemicals, CSIR—Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, India A. Ghosh Academy of Scientific and Innovative Research (AcSIR), CSIR—Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, India Discipline of Plants Omics, CSIR—Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, India