ABSTRACT
Biodiesel is a renewable fuel of commercial interest, driven in part by the rising cost of fossils and negative environmental impacts associated with conventional fuel sources (Sadeghinezhad et al., 2014). First-generation biodiesel was produced from biomass, vegetable oils, animal fats, and waste oils by transesterication (van Eijck et al., 2014). The use of edible oils for rst-generation biodiesel has resulted in the undesired effect of increasing global competition for food crops (Kumar and Sharma, 2015; Pinzi et al., 2014). Second-generation biofuels utilize noncompeting crops such as jatropha, karanja, jojoba, and mahua as well as the use of waste cooking oil, grease, and animal fats. While the use of “inedible” crops reduces competition with food crops, second-generation biofuels still compete for arable land, which ultimately negatively impacts the world food supply and can contribute to the destruction of soil resources, and these feedstock cannot meet the current energy demands (Nautiyal et al., 2014; Zhu et al., 2014). Sustainable alternatives that can provide the large fuel volumes required must be found, while not compromising the use of agricultural land for food production. Microalgae have attracted attention as a means of addressing rapidly growing demand for feedstock in biodiesel production (Baganz et al., 2014; Bellou et al., 2014; Chen et al., 2015b). Microalgae are easy to cultivate and can be grown on nonarable land, as well as accumulate more lipids as a percentage of their biomass than plants (Challagulla et al., 2015).
