Carboxymethyl cellulose as a C-source for lipid accumulation by the oleaginous yeast Candida orthopsilosis

Abstract

Kanti A, Sudiana IM 2015 – Carboxymethyl cellulose as C-source for lipid accumulation by oleaginous Yeast Candida orthopsilosis. Abstract The objective of this study was to evaluate the possibility of using carboxymethyl cellulose (CMC) as a carbon source for lipid accumulation by oleaginous yeasts: Candida orthopsilosis Y09GS34, Candida oleophila Y09GS48, and Lipomyces sp. 10381. Lipid accumulation in the cells was determined by the Nile Red method and lipid composition was identified by gas chromatography mass spectrometry (GC-MS). During the incubation period, CMC-ase activities were monitored to determine the hydrolytic activities of oleaginous yeasts. The results of the study showed that the cellulase activity of all strains tested (Y09GS34, Y09GS48, and 10381) was higher in N-limited medium with 2% CMC, namely 1.193, 0.633 and 1.233 units per hour, respectively. Y09GS34 showed the highest lipid accumulation (63.75% per cell dry weight). The lipid composition of Candida orthopsilosis (Y09GS34) included palmitic acid, stearic acid, linoleic acid, and oleic acid, implying that Candida orthopsilosis (Y09GS34) could utilize cellulose as a carbon source for lipid accumulation. Thus, our study demonstrates that cellulose can be used as a carbon source for lipid accumulation by oleaginous yeasts, and Y09GS34 has the potential to be used for bio-fuel research. Introduction Exploration of renewable energy resources is a common interest of many scientists (Jansson et al.2009, Felice et al. 2012, Sudiana et al. 2014). Exploitation of oleaginous yeast and fungi, which have the ability to accumulate lipids up to > 20% of their dry weight, offer an alternative solution for developing novel renewable energy sources (Liang & Jiang 2013, Kanti et al. 2013). The yeast should be able to use agricultural waste hydrolysate for neutral lipid accumulation to enable their use to the fullest potential (Gao et al. 2014). Oleaginous yeast offer several advantages as lipid sources. These include a rapid cell doubling time, the ability to use various carbon sources for lipid accumulation (Fontanille et al. 2012), and production of large amounts of high biomass in limited space. Unlike plants, their growth is not limited by weather and climate (Cheirsilp et al. 2011, Galafassi et al. 2012) and their intra cellular lipid composition can be manipulated (Sitepu et al. 2013). Agricultural waste is one of the renewable resources that have the potential to be used as a substrate for oleaginous yeasts (Cheirsilp & Louhasakul 2013). Recently, the agricultural sector and business has grown rapidly, which is beneficial to the country. These activities generate large amounts of agricultural wastes, which can be