The commercial potential for microalgae represents a largely untapped resource, once there is a huge number of algae species. Some microalgae are mainly used to human nutrition, but are suitable for preparation of animal feed supplements. Like a biorefinary, it is possible to produce from biofuel and coproducts (espe­cially glycerin) to pigments and nutraceuticals.

The production of microalgae started in the early 1960s with the culture of Chlorella as a food additive and had expanded in others countries (Japan, USA, India, Israel, and Australia) until 1980s (Brennan and Owende 2010). The oil (tri­glycerides) extract from microalgae Chlorella, produced by dark fermentation, has high nutrient value and protein content, and their omega-3 fatty acid—DHA has been used as an ingredient in infant formulas (Brennan Owende 2010; Benemann 2012). D. salina is exploited for its beta-carotene content. Many strains of cyanobacteria (e. g., Spirulina) have been studied to “produce the neurotoxin b-N-methylamino — L-alanine (BMAA) that is linked to amyoptrophic lateral sclerosis-parkinsonism dementia complex, Lou Gehrig’s disease (ALS), and Alzheimer’s disease” (Brennan and Owende 2010, p. 572). The human consumption of microalgae biomass is restricted to very few species (Chlorella, Spirulina, and Dunaliella species domi­nate the market) due to the strict food safety regulations, commercial factors, market demand, and specific preparation. According to Subhadra and Edwards (2011),

a market survey of global algal producers indicated that more companies are planning to grow algae and extract the O3FA to market to consumers […] an immediate market of 0.2-0.4 million ton can be foreseen for algal based O3FA. A small portion can be further refined for marketing as human nutraceuticals and a significant portion for fortifying the AM produced as a co-product by algal biofuel refineries.

In the end of biodiesel production, it is possible to obtain a significant amount of glycerin that “there is a clear existing market from many industries such as paint and pharmaceuticals.” Some studies “have also shown that glycerin in turn can be effectively utilized to grow more algal biomass, another viable method of using glycerin in algal biofuel industry” (Subhadra and Edwards 2011).

Although the microalgae biomass is being produced essentially to human nutritional products, perhaps it is most attractive as animal feeds (Benemann 2012). Algae are the natural food source of aquaculture species such as mol — lusks, shrimps, and fish. In addition, it assists the stabilization, improvement, and enhancement of the immune systems of this cultures (Brennan and Owende 2010). They possess high protein rate (typical 50 %), high energy content (~20 MJ/kg), high concentrations of astaxanthin (used in salmon feed), and valuable carotenoids (e. g., lutein—used in chicken feed). Microalgae have also a long chain of omega-3 fatty acids to replace fish meal/oil (Benemann 2012).