The third element of the strategy was to focus initially onwhat appeared to be the most promising drop-in fuel, biodiesel,as demonstrating economically sustainable production of this bio-fuel would encourage a smooth transition from lower-productivityagricultural biomass (e.g. corn for ethanol) to higher-productivityalgal biomass as a feedstock, while exploiting existing distribu-tion infrastructure. Because lipids can serve as biodiesel precursors,algal strains that accumulate easily extracted lipids in laboratoryculture were chosen for initial development. Initial analyses, usingassumptions then considered conservative suggested that microal-gal biodiesel was potentially economically feasible if productionimprovements could be implemented (Chisti, 2007; Wijffels andBarbosa, 2010; Chisti, 2013; Dassey et al., 2014; Rogers et al., 2014).