Culture of microalgae Chlorella minutissima for biodiesel feedstock production

Abstract

Microalgae are among the most promising of non-food based biomass fuel feedstock alternatives. Algal biofuels production is challenged by limited oil content, growth rate, and economical cultivation. To develop the optimum cultivation conditions for increasing biofuels feedstock production, the effect of light source, light intensity, photoperiod, and nitrogen starvation on the growth rate, cell density, and lipid content of Chlorella minutissima were studied. The fatty acid content and composition of Chlorella minutissima were also investigated under the above conditions. Fluorescent lights were more effective than red or white light-emitting diodes for algal growth. Increasing light intensity resulted in more rapid algal growth, while increasing the period of light also significantly increased biomass productivity. Our results showed that the lipid and triacylglycerol content were increased under N starvation conditions. Thus, a two-phase strategy with an initial nutrient-sufficient reactor followed by a nutrient deprivation strategy could likely balance the desire for rapid and high biomass generation (124 mg/L) with a high oil content (50%) of Chlorella minutissima to maximize the total amount of oil produced for biodiesel production. Moreover, methyl palmitate (C16:0), methyl oleate (C18:1), methyl linoleate (C18:2), and methyl linolenate (C18:3) are the major components of Chlorella minutissima derived FAME, and choice of light source, intensity, and N starvation impacted the FAME composition of Chlorella minutissima. The optimized cultivation conditions resulted in higher growth rate, cell density, and oil content, making Chlorella minutissima a potentially suitable organism for biodiesel feedstock production.

Effect of lake water on algal biomass and microbial community structure in municipal wastewater-based lab-scale photobioreactors

“…The reactors were maintained at a constant temperature of 23±0.5°C (Tang et al 2011), with 16 h of illumination per 24 h to simulate the light/dark cycle conditions of the Swedish summer. Illumination was supplied by four fluorescent tubes at approximately 10,000 lux (∼135 μmol/m 2 s).…”

Impact of nitrogen limitation on biomass, photosynthesis, and lipid accumulation in Chlorella sorokiniana

“…Although N starvation under photoautotrophic growth conditions can result in increased lipid production, many algal strains exhibit slower growth rates in the absence of N, leading to lower overall biomass and energy yields (Huerlimann et al 2010). Some species (C. minutissima), however, are capable of high rates of growth in the absence of N, equivalent to those in N-replete media (Tang et al 2011). This high growth rate in N-deplete media is thought to result from the utilization of stored N reserves rather than from the utilization of N harvested from salvage pathways associated with the turnover of proteins which would be expected to ultimately impair growth (Lourenco and Barbarino 1998).…”

Photosynthetic biogas upgrading to bio-methane: Boosting nutrient recovery via biomass productivity control

“…Despite the slight influence of biomass productivity on TN-REs, 362 the share of the inlet TN assimilated into biomass varied from 19 ± 13 % at the lowest 363 microalgae productivity to 83 ± 9% at the highest productivity (Table 3) profile under nitrogen starvation [33]. The valorization of this microalga into high-403 added value chemicals or biofuels such as syngas, bioethanol or bio-oil using a 404 biorefinery approach will certainly enhance the sustainability and economic viability of 405 microalgae-based biogas upgrading [34].…”