The interest in the bio-based products, namely biofuels and chemicals, has increased in recent years often driven by global concerns about the depletion of the fossil resources and environmental implications. The biomass residues and waste streams from several origins could represent sustainable feedstocks to produce both bioenergy and bio-based products. Microbial oils can be used in a number of oil-based processes, including biodiesel, lubricants, bioplastics production. Their economic feasibility depends on the growing substrates. In order to achieve a feasible production of microbial bio-oils, low-cost substrates are necessary. Aim of the present work was the conversion of un-detoxified hydrolysates of cardoon and raw glycerol from the biodiesel production by Cryptococcus curvatus to develop a cost–effective microbial production of oils. The growth and the lipid production of the oleaginous yeast was assessed at different C/N in batch cultures. The lipids accumulation during the process was monitored through the Nile Red spectrofluorometric analyses. Composition of raw glycerol resulted more inhibitory than cardoon hydrolysate so that no yeast growth was observed above the C/N ratio threshold of 65. The maximum C. curvatus lipid content were 67.2% and 43.7% (g lipids/g cell dry biomass produced %) on cardoon hydrolysate and raw glycerol respectively. The FAME profiles revealed the predominance of fatty acids, namely palmitic, stearic, oleic and linoleic acid, in different percentages depending on the carbon source and on the carbon-to-nitrogen ratios used. The data indicated that the fatty acid compositions depends not only on the C/N ratio but also on the specific carbon source leading to different features and potential applications for the industrial production of renewable chemicals.

Conversion of raw glycerol and cardoon hydrolysate into single cell oil by oleaginous yeasts

Liuzzi F.;Albergo R.;De Bari
2019

Abstract

The interest in the bio-based products, namely biofuels and chemicals, has increased in recent years often driven by global concerns about the depletion of the fossil resources and environmental implications. The biomass residues and waste streams from several origins could represent sustainable feedstocks to produce both bioenergy and bio-based products. Microbial oils can be used in a number of oil-based processes, including biodiesel, lubricants, bioplastics production. Their economic feasibility depends on the growing substrates. In order to achieve a feasible production of microbial bio-oils, low-cost substrates are necessary. Aim of the present work was the conversion of un-detoxified hydrolysates of cardoon and raw glycerol from the biodiesel production by Cryptococcus curvatus to develop a cost–effective microbial production of oils. The growth and the lipid production of the oleaginous yeast was assessed at different C/N in batch cultures. The lipids accumulation during the process was monitored through the Nile Red spectrofluorometric analyses. Composition of raw glycerol resulted more inhibitory than cardoon hydrolysate so that no yeast growth was observed above the C/N ratio threshold of 65. The maximum C. curvatus lipid content were 67.2% and 43.7% (g lipids/g cell dry biomass produced %) on cardoon hydrolysate and raw glycerol respectively. The FAME profiles revealed the predominance of fatty acids, namely palmitic, stearic, oleic and linoleic acid, in different percentages depending on the carbon source and on the carbon-to-nitrogen ratios used. The data indicated that the fatty acid compositions depends not only on the C/N ratio but also on the specific carbon source leading to different features and potential applications for the industrial production of renewable chemicals.
Biomass hydrolysates, Crude glycerol, Cryptococcus curvatus, Oleaginous fermentation
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12079/54765
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