An Outlook on Microalgal Biofuels

Abstract

Microalgae are considered one of the most promising feedstocks for biofuels. The productivity of these photosynthetic microorganisms in converting carbon dioxide into carbon-rich lipids, only a step or two away from biodiesel, greatly exceeds that of agricultural oleaginous crops, without competing for arable land. Worldwide, research and demonstration programs are being carried out to develop the technology needed to expand algal lipid production from a craft to a major industrial process. Although microalgae are not yet produced at large scale for bulk applications, recent advances-particularly in the methods of systems biology, genetic engineering, and biorefining-present opportunities to develop this process in a sustainable and economical way within the next 10 to 15 years.

Changes in Transcript Abundance in Chlamydomonas reinhardtii following Nitrogen Deprivation Predict Diversion of Metabolism

“…The former aspect has been studied since the 1970s. However, focus on the latter has been largely motivated by the renewed interest in microalgae as biofuel feedstocks (Wijffels and Barbosa, 2010). As sequencing technology has become increasingly fast and affordable, comparison of transcriptomic changes under different experimental conditions by massive parallel sequencing of cDNA libraries is a viable first approach toward identifying genes that define changes in response to N deprivation or other nutrient stresses (González-Ballester et al, 2010).…”

“…The search for sustainable sources of biofuels has led to renewed interest in microalgae as a potential feedstock and, consequently, a flurry of research has recently been initiated in microalgae (Wijffels and Barbosa, 2010). Microalgae accumulate large quantities of oils in the form of triacylglycerols (TAGs) when nutrient deprived, and a thorough analysis of the underlying molecular mechanism is currently in its infancy (Hu et al, 2008).…”

Heterotrophy of filamentous oleaginous microalgae Tribonema minus for potential production of lipid and palmitoleic acid

“…Microalgae can grow with CO 2 as the carbon source and sunlight as the energy supply. However, traditional photoautotrophic cultivation of microalgae is highly dependent on the climatic and seasonal conditions, and the long cultivation period, especially low biomass and lipid productivities damage the economic viability and the potential of commercial production (Wijffels and Barbosa, 2010). In comparison to photoautotrophic cultivation, heterotrophic fermentation allows microalgal cells to grow very fast, accumulate dense biomass and lipid oil within less time and the scale-up is much easier.…”

Biofilm cultivation of the oleaginous microalgae Pseudochlorococcum sp.

“…Of all the potential feedstock for biofuels, microalgae are believed to be the only possible feedstock that may significantly replace petroleum-based fuels due to its high productivity potential, less competition with food production and wide adaptability to growth environment when compared with other biomass feedstock options [2][3][4]. However, though intensive efforts have been made in the past few years on microalgae biofuels [5,6], none of the microalgae production systems at the commercial scale have been set up due to their low efficiency and high cost of mass cultivation [4,7]. Currently, the prevailing microalgae culturing devices are open ponds and a variety of closed photobioreactors (PBRs), both of which are based on suspension cultivation.…”