Production of biofuels from marine macroalgae Melanothamnus afaqhusainii and Ulva fasciata

This research article is based on the production of biofuels from the marine macro red alga melanothamnus afaqhusainii and marine macro green alga ulva fasciata from the karachi coast. m. afaqhusainii was investigated for biodiesel as well as for bioethanol whereas u. fasciata was investigated only for bioethanol. two types of biodiesels namely fatty acid methyl ester (fame) and fatty acid ethyl ester (faee) were prepared by the transesterification of algal oil. the carbohydrates from both algae were extracted by distilled water and subjected to different biochemical tests. it was hydrolyzed by various methods including acidic and basic as well as by using ammonia,hydrogen peroxide and mixture of organic solvents in the presence of alcl 3. the comparative study of these methods revealed their efficiency order as naoh (10%)/heating (method-2) > naoh (10%)/h2o2 in microwave oven (method-5) > ammonia (50%)/reflux (method-6). after hydrolysis,the presence of carbohydrates in the hydrolyzed samples was investigated by different biochemical tests including molisch test,iodine test,benedict's test,tollen test,barfoed's test,fehling's solution test,osazone test,seliwanoff's test and bial's test. in addition,the presence of glucose was confirmed by glucometer and combur test. the detailed investigation of carbohydrates was carried out that resulted in the identification of reducing sugars,polysaccharides,disaccharides and monosaccharides including glucose. the hydrolyzed samples were fermented by saccharomyces cerevisiae under ground and paratial anaerobic conditions. the bioethanol so formed by fermentation was directly converted to uv active derivatives namely ethyl benzoate and benzyl acetate. they were confirmed by tlc examination in comparison with standard ethyl benzoate and benzyl acetate. uv spectrophotometer was used for the determination of total sugar and bioethanol on the basis of absorbance by comparing with standards. this valuable research will be fruitful to overcome the current environmental threats. © 2015,chemical society of pakistan. all rights reserved.