Microalgal triacylglycerides production in outdoor batch-operated tubular PBRs

Biotechnology for Biofuels

Giulia Benvenuti³  Rouke Bosma³  Anne J Klok³  Fang Ji²  Packo P Lamers³  Maria J Barbosa⁴  René H Wijffels¹ 

[1] Biosciences and Aquaculture, Nordland University, Bodø, 8049, Norway

[2] Biomass Engineering Center, China Agricultural University, Beijing 100083, China

[3] Bioprocess Engineering, AlgaePARC, Wageningen University, Wageningen, 6700 AA, The Netherlands

[4] Food and Biobased Research, AlgaePARC, Wageningen UR, Wageningen, 6700 AA, The Netherlands

关键词: Light availability;    Pilot-scale;    Outdoor;    TAG productivity;    Microalgae;   

Others  :  1219142
DOI  :  10.1186/s13068-015-0283-2

 received in 2015-03-20, accepted in 2015-07-02,  发布年份 2015

【 摘 要 】

Background

Microalgal triacylglycerides (TAGs) are a promising sustainable feedstock for the biofuel, chemical and food industry. However, industrial production of microalgal products for commodity markets is not yet economically viable, largely because of low microalgal productivity. The latter is strictly dependent on initial-biomass-specific (IBS) light availability (i.e. ratio of light impinging on reactor ground area divided by initial biomass concentration per ground area). This study investigates the effect of IBS-light availability on batch TAG production for Nannochloropsis sp. cultivated in two outdoor tubular reactors (i.e. vertical and horizontal) at different initial biomass concentrations for the TAG accumulation phase, during two distinct seasons (i.e. high and low light conditions).

Results

Increasing IBS-light availability led to both a higher IBS-TAG production rate and TAG content at the end of the batch, whereas biomass yield on light decreased. As a result, an optimum IBS-light availability was determined for the TAG productivity obtained at the end of the batch and several guidelines could be established. The vertical reactor (VR) should be operated at an initial biomass concentration of 1.5 g L ⁻¹to achieve high TAG productivities (1.9 and 3.2 g m ⁻²day ⁻¹under low and high light, respectively). Instead, the horizontal reactor (HR) should be operated at 2.5 g L ⁻¹under high light (2.6 g m ⁻²  day ⁻¹ ), and at 1.5 g L ⁻¹under low light (1.4 g m ⁻²  day ⁻¹ ).

Conclusions

From this study, the great importance of IBS-light availability on TAG production can be deduced. Although maintaining high light availabilities in the reactor is key to reach high TAG contents at the end of the batch, considerable losses in TAG productivity were observed for the two reactors regardless of light condition, when not operated at optimal initial biomass concentrations (15–40% for VR and 30–60% for HR).

【 授权许可】

   
2015 Benvenuti et al.

【 图 表 】

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