Biotechnological conversions of bio-diesel derived waste glycerol into added-value compounds by higher fungi: production of biomass, single cell oil and oxalic acid

Agricultural University of Athens, Department of Food Science and Technology, 75 Iera Odos, 11855 Athens, Greece; National Agricultural Research Foundation, Institute of Agricultural Machinery and Constructions, Laboratory of Edible Fungi, 61 Dimocratias street, 13561 Agii Anargyri, Athens, Greece
Industrial Crops and Products 01/2010; DOI: 10.1016/j.indcrop.2009.12.011

ABSTRACT Waste bio-diesel derived glycerol was used as the sole carbon source by higher fungi; two Lentinula edodes strains were flask cultured in carbon-limited conditions and displayed satisfactory growth in media presenting weak agitation, pH 4.0 and temperature 25 °C. Maximum biomass of 5.2 g/l was produced. Mycelia were synthesized, containing around 0.1 g of fat per g of biomass, with linoleic acid (Δ9,12C18:2) being the principal cellular fatty acid produced. Two Aspergillus niger strains were grown in nitrogen-limited flask cultures with constant nitrogen and two different initial glycerol concentrations into the medium. In 250-ml flask cultures, large-sized pellets were developed, in contrast with the trials performed in 2-l flasks. Nitrogen limitation led to oxalic acid secretion and intra-cellular lipid accumulation; in any case, sequential production of lipid and oxalic acid was observed. Initially, nitrogen limitation led to lipid accumulation. Thereafter, accumulated lipid was re-consumed and oxalic acid, in significant quantities, was secreted into the medium. In large-sized pellets, higher quantities of intra-cellular total lipid and lower quantities of oxalic acid were produced and vice versa. Maximum quantities of oxalic acid up to 20.5–21.5 g/l and lipid up to 3.1–3.5 g/l (corresponding to 0.41–0.57 g of fat per g of biomass) were produced. Lipid was mainly composed of oleic (Δ9C18:1) and linoleic (Δ9,12C18:2) acids.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study compares a traditional agricultural approach to minimise N pollution of groundwater (incorporation of crop residues) with applications of small amounts of biodiesel co-product (BCP) to arable soils. Loss of N from soil to the aqueous phase was shown to be greatly reduced in the laboratory, mainly by decreasing concentrations of dissolved nitrate-N. Increases in soil microbial biomass occurred within 4 days of BCP application-indicating rapid adaptation of the soil microbial community. Increases in biomass-N suggest that microbes were partly mechanistic in the immobilisation of N in soil. Straw, meadow-grass and BCP were subsequently incorporated into experimental soil mesocosms of depth equal to plough layer (23 cm), and placed in an exposed netted tunnel to simulate field conditions. Leachate was collected after rainfall between the autumn of 2009 and spring of 2010. Treatment with BCP resulted in less total-N transferred from soil to water over the entire period, with 32.1, 18.9, 13.2 and 4.2 mg N kg(-1) soil leached cumulatively from the control, grass, straw and BCP treatments, respectively. More than 99 % of nitrate leaching was prevented using BCP. Accordingly, soils provided with crop residues or BCP showed statistically significant increases in soil N and C compared to the control (no incorporation). Microbial biomass, indicated by soil ATP concentration, was also highest for soils given BCP (p < 0.05). These results indicate that field-scale incorporation of BCP may be an effective method to reduce nitrogen loss from agricultural soils, prevent nitrate pollution of groundwater and augment the soil microbial biomass.
    Water Air and Soil Pollution 01/2014; 225:1831. · 1.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Lipids produced from filamentous fungi show great promise for biofuel production, but a major limiting factor is the high production cost attributed to feedstock. Lignocellulosic biomass is a suitable feedstock for biofuel production due to its abundance and low value. However, very limited study has been performed on lipid production by culturing oleaginous fungi with lignocellulosic materials. Thus, identification of filamentous fungal strains capable of utilizing lignocellulosic hydrolysates for lipid accumulation is critical to improve the process and reduce the production cost. The growth performances of eleven filamentous fungi were investigated when cultured on glucose and xylose. Their dry cell weights, lipid contents and fatty acid profiles were determined. Six fungal strains with high lipid contents were selected to culture with the hydrolysate from dilute sulfuric acid pretreatment of wheat straw. The results showed that all the selected fungal strains were able to grow on both detoxified liquid hydrolysate (DLH) and non-detoxified liquid hydrolysate (NDLH). The highest lipid content of 39.4% was obtained by Mortierella isabellina on NDLH. In addition, NDLH with some precipitate could help M. isabellina form pellets with an average diameter of 0.11 mm. This study demonstrated the possibility of fungal lipid production from lignocellulosic biomass. M. isabellina was the best lipid producer grown on lignocellulosic hydrolysates among the tested filamentous fungi, because it could not only accumulate oils with a high content by directly utilizing NDLH to simplify the fermentation process, but also form proper pellets to benefit the downstream harvesting. Considering the yield and cost, fungal lipids from lignocellulosic biomass are promising alternative sources for biodiesel production.
    Biotechnology for Biofuels 07/2012; 5(1):50. · 5.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The biosynthetic potential of four basidiomycetes (Agrocybe aegerita, Flammulina velutipes, Ganoderma applanatum and Pleurotus pulmonarius) and one ascomycete (Morchella esculenta) was examined in regard to biomass, intracellular (endopolysaccharides and lipids) and extracellular (exopolysaccharides) compounds' production in liquid media with glucose as substrate, in static and agitated cultures. Exopolysaccharides' production presented significant negative correlation with biomass, endopolysaccharides and lipids, while biomass was positively related to the production of endopolysaccharides and lipids. Maximum values of biomass, endo- and exo-polysaccharides obtained were quite impressive: P. pulmonarius produced 22.5 g/L of biomass, A. aegerita 60.4 % (w/w) of endopolysaccharides and F. velutipes 1.2 g/L of exopolysaccharides. Polysaccharides and lipids synthesized at the early growth stages were subjected to degradation as the fermentation proceeded. Mycelial lipids of all strains were highly unsaturated, dominated by linoleic acid, whereas glucose was the main building block of endopolysaccharides. The ability of the examined mushroom fungi to synthesize in high quantities biomass and polysaccharides, products with biotechnological and medicinal interest, renders these fungi as potential candidates in sugar-based bio-refineries.
    Bioprocess and Biosystems Engineering 12/2013; · 1.87 Impact Factor


Available from
May 22, 2014