Lipid biosynthesis in Cunninghamella bainieri 2A1 in N-limited and N-excess media

Abstract

Lipid biosynthesis and fatty acids composition of oleaginous zygomycetes, namely Cunninghamella bainieri 2A1, cultured in media with excess or limited nitrogen were quantitatively determined at different times of culture growth. Accumulation of lipids occurred even when the activity of NAD+-ICDH (β-Nicotinamide adenine dinucleotide-isocitrate dehydrogenase) was still detectable in both media. In C. bainieri 2A1, under nitrogen limitation, the ratio of lipids was around 35%, whereas in nitrogen excess medium (feeding media supplemented with ammonium tartarate), the lipid ratio decreased. The amount of this decrease depended on the level of ammonium tartarate in the media. The main findings in this paper were that C. bainieri 2A1 has the ability to accumulate lipid although nitrogen concentration detected inside the media and that NAD-ICDH was active in all culture periods. These results proved that the strain C. bainieri 2A1 has an alternative behavior in lipid biosynthesis that differs from yeast. According to the old hypotheses, yeasts could not accumulate lipid more than 10% when nitrogen was detected inside the media. Nitrogen-limited and excess media both contained the same fatty acids (palmitic acid, stearic acid, olic acid, linoleic acid and γ-linolenic acid), but at different concentrations. The C:N ratio was also studied and showed no effects on total lipid accumulation, but a significant effect on γ-linolenic acid concentration.

Batch culture and repeated-batch culture of Cunninghamella bainieri 2A1 for lipid production as a comparative study

“…Previous studies have revealed that a high amount of lipid could be accumulated by the fungal species of Cunninghamella depending on the fermentation methods and culture conditions (Fakas et al, 2007, Fakas et al, 2009, Somashekar et al, 2003). Similar studies have shown that a high lipid accumulation is attained by Cunninghamella bainieri 2A1 in the submerged batch culture (Taha et al, 2010). It is well known that C. bainieri 2A1 is capable of producing up to 30% lipid (g/g biomass) which contains 10–15% GLA.…”

Optimization of Aeration and Agitation Rate for Lipid and Gamma Linolenic Acid Production byCunninghamella bainieri2A1 in Submerged Fermentation Using Response Surface Methodology

“…depending on the fermentation methods and culture conditions [ 5 , 6 ]. Similar studies have shown that a high lipid accumulation is attained by Cunninghamella bainieri 2A1 in shake flask culture [ 7 ]. It is worth noticing that microbial lipids are mostly comprised of triacylglycerols (TAGs) with the lower quantities of free fatty acids, natural lipids (monoacylglycerols, diacylglycerols, and steryl-esters), sterols, and polar fractions such as phospholipids, sphingolipids, and glycolipids.…”

Isolation of Cunninghamella bigelovii sp.nov. CGMCC 8094 as a new endophytic oleaginous fungus from Salicornia bigelovii

“…It has been reported that several species of Cunninghamella, such as C. elegans (Čertík et al 1993), C. echinulata (Fakas et al 2006) and C. bainieri (Taha et al 2010), can accumulate lipids in their cells, and these species have consequently been designated as oleaginous (Certik et al 1999). According to this definition, C. bigelovii would be an oleaginous fungus.…”