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Macroalgae (mainly marine macroalgae, i.e. seaweeds) are considered as a very promising source for bioethanol production, because they have high carbohydrate contents, superior productivity, and wide adaptability. Macroalgae are generally grouped into three major categories: red, green, and brown algae. Each category has thousands of species, and each species possesses its unique cellular structure, biochemistry, and constitutes. Converting macroalgae to bioethanol involves pretreatment, saccharification, fermentation, and distillation; and the establishment of economic pretreatment methods is always the first key step for bioethanol production. In present, dilute-acid or alkali hydrolysis is typically used to treat macroalgal biomass. Macroalgae can be depolymerized under mild conditions as they have low lignin content. The resulting polysaccharides can be converted to ethanol through enzymatic hydrolysis, followed by adding bacteria, such as Saccharomyces cerevisiae and recombinant Escherichia coli KO11. Compared with the separate hydrolysis and fermentation process, the simultaneous saccharification and fermentation process often provided higher ethanol titer and conversion efficiency. However, the research on bioethanol production from macroalgae is still in its early stage due to both technical and economic barriers, significant amount of research and development work is needed prior to the commercialization of bioethanol manufacture from macroalgae. 

Red seaweeds are the major source of economically important colloids, agar and carrageenan. Agar industry in India shall become commercially attractive only when the yield of agar from the raw material is enhanced. Inherently most Indian agarophytes contain 10-20% agar only. Though species of Gelidiella and Gelldium contain 35-50% agar and the quality of agar in terms of gel strength is also superior, their biomass production is very less, occurrence is seasonal and their exploitation is difficult. Hence an attempt is underway to obtain a hybrid strain of red seaweed for large scale mariculture between slow growing but high agar containing seaweed and fast growing, poor agar yielders. This article enumerates the prospective areas of seaweed biotechnology and its immediate relevance to seaweed mariculture and the related industry in India.

Seaweeds constitute one of the commercially important marine living renewable resources. They are used as human food, feed for animals, fertilizer for land crops, source of chemicals and drugs. The estimated total standing crop of seaweeds from intertidal and shallow waters of all maritime states, Lakshadweep and Andaman was 91,339 tons (wet wt.). The quantity of seaweeds estimated in deep waters of Tamilnadu was 75,373 tons (wet wt.) in an area of 1863 sq.km. from Dhanushkodi to Kanyakumari.

Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC50 scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo.