HIGHLIGHTSTotal micro-phytoplankton count amounted to 6.59±1.27x10 5 cells L -1 which was dominated by diatoms (95.2%), followed by dinoflagellates (2.9%) and cyanobacteria (1.9%).  The cyanobacterial mats were identified as Leptolyngbya sp. and Nodularia harveyana, and the endosymbiotic dinoflagellates as the Symbiodinium clade C.  There were also differences recorded in the % lipid of the different microalgae (p<0.005) -among all, Symbiodinium clade C had the highest with (38.39±6.58%). The aim of this study was to assess the lipid content and the subsequent potential of different microalgae present in the Mauritian marine water to produce biodiesel. The share of micro-phytoplankton species in the water column was determined. The cyanobacterial mats and endosymbiotic dinoflagellates were characterised morphologically and genetically using RFLP. The samples were quantified gravimetrically and analysed using 1 H & 13 C NMR spectroscopy. Total micro-phytoplankton count amounted to 6.59±1.27x10 5 cells L -1 which was dominated by diatoms (95.2%), followed by dinoflagellates (2.9%) and cyanobacteria (1.9%). The cyanobacterial mats were identified as Leptolyngbya sp. and Nodularia harveyana, and the RFLP characterised the endosymbiotic dinoflagellates as the Symbiodinium clade C. The highest amount of lipid was recorded in the Symbiodinium clade C (38.39±6.58%).1 H and 13 C NMR analyses indicated the presence of acyl glycerols. An attempt to synthesise biodiesel by alkaline trans-esterification reaction was also performed and the presence of biodiesel was detected using the Fourier Transform Infrared Spectroscopy. The Infrared analysis yielded peaks at around 1738cm -1 and 1200cm -1 characteristic of the carbonyl and ether groups respectively, indicating the presence of biodiesel.

Marine algae are of high importance in their natural habitats and even more now in the world of green technology. The sprouting interest of the scientific community and industries in these organisms is driven by the fast-growing world of modern biotechnology. Genomics, transcriptomics, proteomics, metabolomics and their integration collectively termed here as 'marine algal-omics' have broadened the research horizon in view of enhancing human's life by addressing environmental problems and encouraging novelty in the field of pharmaceuticals among so many more. Their use in the human society dates back to 500 B. C. in China and later across the globe; they are still being used for similar purposes and more today. There is a hiking interest in marine algae and their derivatives-from phycoremediation, food supplements, pharmaceuticals to dyes. Marine algae are currently considered as an emerging panacea for the society. They are being studied in a multitude of arenas. The multi-use of marine algae is enticing and promises to be a boon for industrial applications. Yet, most marine algae face challenges that might variably constrain their commercialisation. This chapter gives an overview of marine algae including all the 'omics' technologies involved in studying marine algae and it explores their multitude applications. It also draws the various successful industries budded around them and presents some of the challenges and opportunities along with future directions.