Growth of mono- and mixed cultures of Nannochloropsis salina and Phaeodactylum tricornutum on struvite as a nutrient source

Abstract

The suitability of crude and purified struvite (MgNH4PO4), a major precipitate in wastewater streams, was investigated for renewable replacement of conventional nitrogen and phosphate resources for cultivation of microalgae. Bovine effluent wastewater stone, the source of crude struvite, was characterized for soluble N/P, trace metals, and biochemical components and compared to the purified mineral. Cultivation trials using struvite as a major nutrient source were conducted using two microalgae production strains, Nannochloropsis salina and Phaeodactylum tricornutum, in both lab and outdoor pilot-scale raceways in a variety of seasonal conditions. Both crude and purified struvite-based media were found to result in biomass productivities at least as high as established media formulations (maximum outdoor co-culture yield ∼20±4gAFDW/m(2)/day). Analysis of nutrient uptake by the alga suggest that struvite provides increased nutrient utilization efficiency, and that crude struvite satisfies the trace metals requirement and results in increased pigment productivity for both microalgae strains.

Trends in Synthetic Biology in the Bioeconomy of Non-food-Competing Biofuels

“…The use of microalgae has enormous energy potential, given the possibility of transforming CO2 and heat into chemical energy at scales much larger than those produced by terrestrial plants [110], without competing with food production. P. tricornutum is a strain with significant biotechnological potential for future photosynthetic biorefineries [41]. New species of microalgae, including Scenedesmium sp NBRI012, have high productivity of biomass, carbohydrates, and lipid content.…”

“…It is not new that microalgae have enormous biosynthetic potential under adverse physiological conditions [11,37], being recognized as a propitious source for the sustainable production of bio-based fuels [25,118]. P. tricornutum is a model microalga with biotechnological potential for future biorefineries [41]. Microalgae are photosynthetic microorganisms capable of lipid accumulation by transforming CO2 and heat into chemical energy at scales larger than those of terrestrial plants [110,119].…”

“…Microalgae are photosynthetic microorganisms capable of lipid accumulation by transforming CO2 and heat into chemical energy at scales larger than those of terrestrial plants [110,119]. Besides, they can use wastewater [41,42], which reduces the need for other valuable nutrients. Therefore, the research focuses on the genomics of the metabolism related to the formation and accumulation of lipids [120,121].…”

“…Non-native Yarrowia lipolytica yeast presents an industrial potential for fatty acidproducing platforms from cheap and renewable routes [39]. Microalgae have enormous potential for biofuel production due to their high cell growth rate and can be grown on marginal lands [40,11,15], and wastewater [41,42] thus reducing the need for nutrients for the growth of photosynthetic cells.…”

Assessing the potential of polyculture to accelerate algal biofuel production

“…This risk may be minimized by assembling the polyculture only with very fast growing and stable strains that are difficult to outcompete by invasive species. Davis et al [178] demonstrated the stable biomass growth in a mixed outdoor pond culture of Nannochloropsis salina and Phaeodactylum tricornutum [178]. Similarly, a binary designed culture consisting of fast growing Chlorella and Scenedesmus strains remained free of invasive species in an outdoor pond culture experiment (PNNL unpublished data).…”