Biochemical Modulation of Lipid Pathway in MicroalgaeDunaliellasp. for Biodiesel Production

Abstract

Exploitation of renewable sources of energy such as algal biodiesel could turn energy supplies problem around. Studies on a locally isolated strain of Dunaliella sp. showed that the mean lipid content in cultures enriched by 200 mg L−1 myoinositol was raised by around 33% (1.5 times higher than the control). Similarly, higher lipid productivity values were achieved in cultures treated by 100 and 200 mg L−1 myoinositol. Fluorometry analyses (microplate fluorescence and flow cytometry) revealed increased oil accumulation in the Nile red-stained algal samples. Moreover, it was predicted that biodiesel produced from myoinositol-treated cells possessed improved oxidative stability, cetane number, and cloud point values. From the genomic point of view, real-time analyses revealed that myoinositol negatively influenced transcript abundance of AccD gene (one of the key genes involved in lipid production pathway) due to feedback inhibition and that its positive effect must have been exerted through other genes. The findings of the current research are not to interprete that myoinositol supplementation could answer all the challenges faced in microalgal biodiesel production but instead to show that “there is a there there” for biochemical modulation strategies, which we achieved, increased algal oil quantity and enhanced resultant biodiesel quality.

Manipulation of carbon flux into fatty acid biosynthesis pathway in Dunaliella salina using AccD and ME genes to enhance lipid content and to improve produced biodiesel quality

“…The excitation and emission wavelengths of 522 and 628 nm, respectively, were selected based on a previous report by Talebi et al (2014b).…”

“…Similar observations have been reported when lipid production is enhanced through biochemical engineering approaches. For instance, Talebi et al (2014b) achieved a 50% increase in total lipid accumulation through myo-inositol supplementation, as a lipid inducer treatment in D. salina. while also reported 54% deacrease in USFA/FAME.…”

Microalgal swimming signatures and neutral lipids production across growth phases

“…Such a system would improve control of cultivation conditions and harvest timing of microalgae, leading to a substantial biofuel yield and low‐cost algae‐based biofuels. Conventional methods for intracellular neutral lipid determination, such as lipid separation by column or thin‐layer chromatography, fatty acid profiling by gas chromatography, and fluorometric determination of neutral lipids by Nile red/BODIPY (W. Chen et al, 2009; Cooksey, Guckert, Williams, & Callis, 1987; Elsey, Jameson, Raleigh, & Cooney, 2007; Govender, Ramanna, Rawat, & Bux, 2012; Moheimani, Borowitzka, Isdepsky, & Sing, 2013; Siaut et al, 2011; Talebi et al, 2015; Yang, He, & Hu, 2015), either require tedious extraction and/or transesterification work and expensive equipment or test only small volume samples which are less representative for large‐scale cultivations. In contrast to current lipid measurement methods, DIH‐PTV has much higher throughput and better scalability.…”

Gene Expression Analysis in Dunaliella salina Under Salt Stress

“…The microalgae Dunaliella Salina was prepared from plant biotechnology laboratory of Ferdowsi university of Mashhad with accession number KF477384 and algae cells grown in 500 ml Erlenmeyer flasks containing 250 ml culture medium (Talebi et al, 2015). Culture media formulated using several trails and errors, contained the following compositions as in 1 L distilled water: 1.50 g NaNO 3 , 1.00 g KNO 3 , 3 g NaHCO 3 , 0.080 g CaCl 2 .…”