Nannochloropsis production metrics in a scalable outdoor photobioreactor for commercial applications

Commercial production of renewable energy feedstocks from microalgae will require reliable and scalable growth systems. Two and one half years of biomass and lipid productivity data were obtained with an industrial-scale outdoor photobioreactor operated in Fort Collins, Colorado (USA). The annualized volumetric growth rates for Nannochloropsis oculata (CCMP 525) and Nannochloropsis salina (CCMP 1776) were 0.16 g L−1 d−1 (peak = 0.37 g L−1 d−1) and 0.15 g L−1 d−1 (peak = 0.37 g L−1 d−1) respectively. The collective average lipid production was 10.7 m3 ha−1 yr−1 with a peak value of 36.3 m3 ha−1 yr−1. Results from this study are unique based on publication of biomass and corresponding lipid content combined with demonstration of energy savings realized through analysis of gas delivery requirements, water recycling from successive harvests with no effect on productivity, and culture stability through serial batch lineage data and chemotaxonomic analysis of fatty acid contents.

► Growth rates averaged 0.16 g L−1 d−1 during calendar years of 2009 & 2010.
► Peak growth rate of 0.37 L−1 d−1.
► Average bio-oil productivity of 10.7 m3 ha−1 yr−1 with peak of 36.3 m3 ha−1 yr−1.
► Serial batch cultures maintained for >421 days of continuous cultivation.
► Energy consumption sensitivity analysis for large-scale photobioreactor system.