Lipid productivity and cell wall ultrastructure of six strains of Nannochloropsis: Implications for biofuel production and downstream processing

• Published in: Algal research (Amsterdam) 2014-10, Vol.6, p.64-69
• Main Authors: Beacham, Tracey A., Bradley, Claire, White, Daniel A., Bond, Peter, Ali, Sohail T.
• Format: Article
• Language: English
• Subjects: Biofuels; Fatty acid; Lipid; Microalgae; Nannochloropsis; Ultrastructure
• ISSN: 2211-9264; 2211-9264
• DOI: 10.1016/j.algal.2014.09.003

Microalgae are generating considerable interest for third generation biodiesel production. However, appropriate strain selection is proving challenging due to the significant variation in cellular physiology, metabolic potential and genetics observed even amongst strains deemed morphologically similar. Six strains of Nannochloropsis from the CCAP culture collection were assessed for their lipid productivity and cellular structure, as proxies for oil production and harvesting ease, to assess their suitability as biodiesel production platforms. Differences in growth rate and lipid accumulation across the strains were observed. Nannochloropsis oculata strain 849/7 showed significantly reduced doubling time compared to Nannochloropsis salina strain 849/3, whilst Nannochloropsis oceanica 849/10 produced the highest lipid content. In addition the six strains could be differentiated into 3 distinct classes based on their cell wall thickness, which varied across the strains from 63 to 119nm and which is independent of both species and geographical isolation location. The importance of these variations in ultrastructure and physiology for biodiesel production is discussed. •Total FAME content varied from 3.5% to 14.7% across six Nannochloropsis strains.•Strains fall into three independent groups based on cell wall thickness irrespective of species or geographical isolation.•Moderate salinity changes (up to 20%) do not hinder growth of N. salina.•Semi-continuous harvesting could increase productivity by approximately 39%.