Sources and resources: importance of nutrients, resource allocation, and ecology in microalgal cultivation for lipid accumulation.

Matthew W Fields,Adam Hise,Rob D Gardner,Luisa Corredor,Robin Gerlach,Tisza Bell,Gregory W Characklis,Egan J Lohman,Karen Moll,Brent M Peyton

doi:10.1007/s00253-014-5694-7

Abstract

Regardless of current market conditions and availability of conventional petroleum sources, alternatives are needed to circumvent future economic and environmental impacts from continued exploration and harvesting of conventional hydrocarbons. Diatoms and green algae (microalgae) are eukaryotic photoautotrophs that can utilize inorganic carbon (e.g., CO2) as a carbon source and sunlight as an energy source, and many microalgae can store carbon and energy in the form of neutral lipids. In addition to accumulating useful precursors for biofuels and chemical feed stocks, the use of autotrophic microorganisms can further contribute to reduced CO2 emissions through utilization of atmospheric CO2. Because of the inherent connection between carbon, nitrogen, and phosphorus in biological systems, macronutrient deprivation has been proven to significantly enhance lipid accumulation in different diatom and algae species. However, much work is needed to understand the link between carbon, nitrogen, and phosphorus in controlling resource allocation at different levels of biological resolution (cellular versus ecological). An improved understanding of the relationship between the effects of N, P, and micronutrient availability on carbon resource allocation (cell growth versus lipid storage) in microalgae is needed in conjunction with life cycle analysis. This mini-review will briefly discuss the current literature on the use of nutrient deprivation and other conditions to control and optimize microalgal growth in the context of cell and lipid accumulation for scale-up processes.

Highlights

In modern societies, petroleum-based products and fuels have strongly influenced human culture and infrastructure
The scale-up of photobioreactor system (PBR) is challenged by proper gas exchange and pH maintenance, but has mostly been discouraged by concerns over higher capital expense (Rawat et al 2013). The latter has often led to pessimism regarding the use of PBRs for large-scale algae production, but recent studies have suggested that the higher productivity resulting from control of growth parameters leads to lower overall costs than those observed with open raceway ponds (ORPs) (Norsker et al 2011)
With the reinvigorated interest in alternative fuels, microalgae provide one option that will likely contribute to an overall plan for biomass, biochemical, and biofuel production in a more sustainable and efficient manner

Summary

Introduction

Petroleum-based products and fuels have strongly influenced human culture and infrastructure. This mini-review will briefly discuss the current literature on the use of nutrient deprivation and other conditions to control and optimize microalgal growth in the context of cell and lipid accumulation for scale-up processes. This mini-review will briefly discuss the current literature on the use of nutrient deprivation and other conditions to control and optimize microalgal culture growth in the context of cell and lipid accumulation.

Results

Conclusion