Integrated production of algal biofuels and biocommodities

A marine algal production and processing facility was set up in Navi Mumbai, India for integrated production of algal biofuels and biocommodities that included a number of new methods of production and processing. It included a sunlight distribution-based 100,000 L/220 m2 algal growth system (open) that was found to give improved productivity over raceway pond at earlier scales; a harvest mechanism based on self-aggregating feature of select algae; a 100 L wet algal lipid extraction unit that can process wet algal paste without the need for drying at normal temperature and pressure using biocompatible industrial solvents. A variety of coproducts – aquafeed, cattle feed, food packaging biodegradable plastics, cellulose nanocrystal platform chemical, pyrolytic bio-oil, biohydrogen – were developed for value-addition. Algal growth in the growth system was characterized by significant contamination challenges posed by the highly biodiverse backwater location until a high salinity-tolerant alga was adopted which resulted in a sustained productivity of 15.1 g/m2/day. The wet algal lipid extraction unit (based on a method that yielded full lipid recovery at lab-scale) resulted in an extraction efficiency of 90.1 % ± 19.2 %. Aquafeed from deoiled algae showed promising results and offers the most immediate prospects for value-addition among the various coproducts developed. Food packaging biodegradable plastics from deoiled algae has shown properties better than those from other feedstock. Technoeconomic analysis showed that at realistically pursuable targets of 25 g/m2/day productivity and 20 % lipid content at a scale of 130 ha, algal biofuel can be produced at $ 1.02/L with value-addition from aquafeed as coproduct from deoiled algae. The target range was $ 0.8–1.0/L. The influence of parameters on the final biofuel cost can be summed up in the following order and degree: scale > > coproduct value-addition > algal productivity > > contamination control > lipid content > lipid extraction efficiency.