Dose-response Assessment Upon CO2 Tolerance of Indigenous Microalgal Isolates for Biofuel Production

AbstractTo select optimal CO2-tolerant microalgal species for simultaneous renewable biodiesel production and reduction of greenhouse-gas emission, this study proposed first-attempt toxicological assessment to screen CO2-utilizing microalgal isolates from natural water bodies present in highly biodiverse eastern Taiwan. With specified culture media (e.g., BG-11 medium) at different temperatures and CO2 concentrations, the ranking of growth characteristics (μ; d-1) of microalgal isolates was determined (e.g., Chlorella sp. NIUs08 (0.233d−1)>Scenedesmus sp. NIUs06 (0.17d−1)>Chlorella sp. NIUs07 (0.0914d−1)>strain NIUs05 (0.085d−1)>Chlorella sp. NIUs09 (0.038d−1)). In terms of toxicology, this study provided novel dose-response assessment upon microalgal growth in response to CO2-inhibitory potency, suggesting promising isolates for cost-effective applications of CO2 reduction. Although CO2 could be utilized as sole carbon source for microalgal growth, algal tolerance to CO2 inevitably controls the performance of growth-associated production. Thus, this first-attempt novel assessment quantitatively revealed the most promising CO2-utilizing microalgae obtained from estuarine water, in particular for renewable-bioenergy applications to high level CO2 emission industry