Yeast lipids from cardoon stalks, stranded driftwood and olive tree pruning residues as possible extra sources of oils for producing biofuels and biochemicals

Abstract

BackgroundSome lignocellulosic biomass feedstocks occur in Mediterranean Countries. They are still largely unexploited and cause considerable problems due to the lack of cost-effective harvesting, storage and disposal technologies. Recent studies found that some basidiomycetous yeasts are able to accumulate high amount of intracellular lipids for biorefinery processes (i.e., biofuels and biochemicals). Accordingly, the above biomass feedstocks could be used as carbon sources (after their pre-treatment and hydrolysis) for lipid accumulation by oleaginous yeasts.ResultsCardoon stalks, stranded driftwood and olive tree pruning residues were pre-treated with steam-explosion and enzymatic hydrolysis for releasing free mono- and oligosaccharides. Lipid accumulation tests were performed at two temperatures (20 and 25 °C) using Leucosporidium creatinivorum DBVPG 4794, Naganishia adeliensis DBVPG 5195 and Solicoccozyma terricola DBVPG 5870. S. terricola grown on cardoon stalks at 20 °C exhibited the highest lipid production (13.20 g/l), a lipid yield (28.95%) close to the maximum theoretical value and a lipid composition similar to that found in palm oil. On the contrary, N. adeliensis grown on stranded driftwood and olive tree pruning residues exhibited a lipid composition similar to those of olive and almonds oils. A predictive evaluation of the physical properties of the potential biodiesel obtainable by lipids produced by tested yeast strains has been reported and discussed.ConclusionsLipids produced by some basidiomycetous yeasts grown on Mediterranean lignocellulosic biomass feedstocks could be used as supplementary sources of oils for producing biofuels and biochemicals.

Multi-Step Exploitation of Raw Arundo donax L. for the Selective Synthesis of Second-Generation Sugars by Chemical and Biological Route

“…For this reason, Arundo donax L. is widely used as a substrate for the synthesis of important platform-chemicals, biofuels, and second-generation sugars [14,16,25,27,35,[46][47][48]. In particular, the interest towards the synthesis of xylose and glucose is continuously growing, due to their promising applications in both chemical and biological processes to produce alcohols, acids, oils, hydrocarbons, hydrogen, and other valuable products [1,15,22,34,46,47,[49][50][51][52][53][54][55]. However, up to now, only a few works discussed the employment of acid solid catalysts for the conversion of Arundo donax L. to value-added products, performing the reaction in the presence of ionic liquids as solvents, which have some criticisms related to their high viscosity, toxicity and cost, which strongly limit the sustainability of this approach.…”

Phosphate removal combined with acetate supplementation enhances lipid production from water hyacinth by Cutaneotrichosporon oleaginosum

“…Results using various lignocellulosic hydrolysates for microbial lipid fermentation by various oleaginous species are summarized in Table 5. Compared to rice straw hydrolysates [39], sugarcane bagasse hydrolysates [40], wheat straw hydrolysates [14, 41], corn stover hydrolysates [17, 20, 42, 43], corncob residues hydrolysates [44], waste paper hydrolysates [45], laminaria residues hydrolysates [19], groundnut shell hydrolysates [46], cardoon stalks hydrolysates [47], and elephant grass hydrolysates [48], the present water hyacinth hydrolysates demonstrated inferior results of lipid production. The herbaceous biomass was nutrients-rich and resulted in very low lipid production.…”

Optimization of enzymatic hydrolysis of cellulosic fraction obtained from stranded driftwood feedstocks for lipid production by Solicoccozyma terricola

“…However, due to their high cellulosic and hemicellulosic content, stranded driftwood feedstocks could be considered suitable C-rich sources for producing chemicals via microbial processes [[6], [7], [8]]. Since some decades oleaginous yeasts are considered potential converters of carbohydrates into lipids due to their ability to accumulate high amounts of intracellular triacylglycerols (TAGs - above 20% of their dry biomass) under appropriate conditions [[9], [10], [11], [12], [13]].…”

“…[14]. Interestingly, TAGs sometimes show fatty acid profiles and technological performances comparable with those exhibited by some vegetable oils [13,15]. According to the literature, one of the main fatty acid produced by oleaginous yeasts is represented by oleic acid.…”

“…Accordingly, in this study a response surface methodology was used to predict the best combination of two independent variables (i.e. the dosage of cellulolytic enzyme cocktail and the solid loading, both related to the enzymatic hydrolysis of cellulose obtained after steam explosion of stranded driftwood feedstocks) in order to optimize the lipid yield achieved by the oleaginous yeast Solicoccozyma terricola DBVPG 5870, which was previously selected as lipid overproducing strain [13,32].…”