John Benemann, CEO, MicroBio Engineering Inc., San Luis Obispo, California
In Japan, the ancestral home of seaweed cultivation, the microalgae industry started in the 1960s with the first Chlorella production for human nutritional supplements, using mixed circular cultivation ponds. By the late 1970s a dozen plants in Japan and Taiwan were producing over 500 metric tons of Chlorella powder, with acetate as a supplemental carbon source for mixotrophic growth. Chlorella production is now over ten-fold higher, mostly in China but also produced in Europe in hectare size photobioreactors. To expand beyond the current limited ‘nutraceuticals’ markets, solar, that is autotrophic and/or mixotrophic, Chlorella production costs must be reduced, through larger-scale systems, more robust algal strains and lower-cost harvesting and biomass processing. Heterotrophic Chlorella production in dark fermenters is a rapidly developing industry, but only sunlight driven process are addressed herein.
Spirulina production started in the 1970s in Mexico and Thailand, then in the US and India, with China now the dominant producer. Annual global production exceeds 10,000 metric tons, almost all produced in large raceway, paddle wheel mixed ponds, with some production inside greenhouses. Recently, many small-scale farms, particularly in France, started producing Spirulina for local markets. The future of industrial Spirulina production is bright, due to likely production cost reductions, increasing recognition by consumers of its unique nutritional values and the expanding use of phycocyanin as food colorant.
The third microalgal product developed commercially was natural beta-carotene from Dunaliella salina, produced since the 1980s in very large (up to 100 ha) open unmixed ponds in Australia and in paddle wheel mixed raceway ponds, first in California and then Israel. There is a strong market demand for this natural product and new, large-scale, producers could compete with low-cost synthetic beta-carotene.
Natural astaxanthin, a powerful antioxidant, has been produced since the late 1990s in many countries at industrial scale with cultures of Haematococcus pluvialis. Tubular photobioreactors were first used in Israel, and this is now the main production technology, with China the largest producer. In Hawaii open ponds are used for H. pluvialis production and some producers use artificial lights. Reducing production costs will lead to larger sales, including in the over a hundred million dollar a year salmon feed market.
The solar microalgae industry appears poised at the inflection point to exponential growth in production volumes, markets and products. This will require more robust, high yield algal strains and overall lower cost production systems. The ‘algal biofuels bubble’ that started a decade ago, with billions of dollars invested, has by now essentially burst. However, that experience built a strong foundation for industrial production of novel microalgal strains, new products, advanced crop protection techniques, and better harvesting and processing technologies. For examples only, EPA production from Nannochloropsis is starting to be commercialized and microalgae applications in wastewater treatment and aquaculture are expanding. Even if not all promises, such as reducing most CO2 emissions from power plants, replacing all jet fuel used by airlines, or feeding starving people around the world, are likely to be realized, the future of the solar microalgae industry shines bright and will benefit all humanity.