Single cell oil of oleaginous fungi from the tropical mangrove wetlands as a potential feedstock for biodiesel

Abstract

Background: Single cell oils (SCOs) accumulated by oleaginous fungi have emerged as a potential alternative feedstock for biodiesel production. Though fungi from mangrove ecosystem have been reported for production of several lignocellulolytic enzymes, they remain unexplored for their SCO producing ability. Thus, these oleaginous fungi from the mangrove ecosystem could be suitable candidates for production of SCOs from lignocellulosic biomass. The accumulation of lipids being species specific, strain selection is critical and therefore, it is of importance to evaluate the fungal diversity of mangrove wetlands. The whole cells of these fungi were investigated with respect to oleaginicity, cell mass, lipid content, fatty acid methyl ester profiles and physicochemical properties of transesterified SCOs in order to explore their potential for biodiesel production. Results: In the present study, 14 yeasts and filamentous fungi were isolated from the detritus based mangrove wetlands along the Indian west coast. Nile red staining revealed that lipid bodies were present in 5 of the 14 fungal isolates. Lipid extraction showed that these fungi were able to accumulate > 20% (w/w) of their dry cell mass (4.14 -6.44 g L -1 ) as lipids with neutral lipid as the major fraction. The profile of transesterified SCOs revealed a high content of saturated and monounsaturated fatty acids i.e., palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids similar to conventional vegetable oils used for biodiesel production. The experimentally determined and predicted biodiesel properties for 3 fungal isolates correlated well with the specified standards. Isolate IBB M1, with the highest SCO yield and containing high amounts of saturated and monounsaturated fatty acid was identified as Aspergillus terreus using morphotaxonomic study and 18 S rRNA gene sequencing. Batch flask cultures with varying initial glucose concentration revealed that maximal cell biomass and lipid content were obtained at 30gL -1 . The strain was able to utilize cheap renewable substrates viz., sugarcane bagasse, grape stalk, groundnut shells and cheese whey for SCO production. Conclusion: Our study suggests that SCOs of oleaginous fungi from the mangrove wetlands of the Indian west coast could be used as a potential feedstock for biodiesel production with Aspergillus terreus IBB M1 as a promising candidate.

Xylitol production byCyberlindnera(Williopsis) saturnus, a tropical mangrove yeast from xylose and corn cob hydrolysate

“…Twenty-one fungal cultures were isolated from mangrove wetlands and maintained on Czapek's Dox agar (CDA) as described by Khot et al (2012 Li et al (2011). Media components were then added to the hydrolysate and filter-sterilized into 500-ml conical flask prior to inoculation.…”

Harnessing Indigenous Plant Seed Oil for the Production of Bio-fuel by an Oleaginous Fungus, Cunninghamella blakesleeana- JSK2, Isolated from Tropical Soil

“…It is eco-friendly, non-toxic, bio-degradable, stable, reduces the level of potential or probable carcinogens, and has a favorable emission profile [3]. It is produced from an array of inexpensive and renewable raw materials such as lignocellulosic biomass [4], plant seed oils [5,6], waste glycerol [7], corn cob waste liquor [8], wheat straw [9], and agro-residues [10]. Utilization of these by-products will make an important contribution in the reduction of overall production costs of biodiesel in the global market which is the major reason for researchers focusing their attention on oleaginous fungi [11,12].…”

New Frontiers in the Production of Biodiesel: Biodiesel Derived from Macro and Microorganisms

“…Authors proposed a mathematical model to simulate the consumption of sugar and nitrogen, the fat-free biomass formation, and the accumulation of lipids (Economou et al 2011). Khot et al (2012) isolated fungi of tropical mangrove wetlands, but only five out of 14 showed lipid accumulation above 20 % dry cell biomass. Fungi from this ecosystem were also used for the production of lignocellulosic enzymes.…”