0000000000376266
AUTHOR
Leobardo Serrano-carreón
Production of 6-pentyl-?-pyrone byTrichoderma harzianum from 18?n fatty acid methyl esters
Biosynthesis of 6-pentyl-α-pyrone byTrichoderma harzianum in two different media was evaluated. Best yields were found in nitrogen deficient medium (C/N=60). Limited growth seems to favour the production of this lactone. When fungal cells, precultured in low nitrogen medium, were incubated on methyl ricinoleate (10 g/l, C/N=60) an increase in 6-pentyl-α-pyrone production was observed in comparison with the media containing methyl oleate or methyl linoleate.
Quantitative separation of Trichoderma lipid classes on a bonded phase column.
Bond Elut aminopropyl columns were used to purify the different lipid classes of Trichoderma harzianum and Trichoderma viride. This methodology permitted good separation of the fungal lipid classes in less time than traditional techniques. The incorporation of [1 (14)C]linoleic acid into neutral lipids, free fatty acids and phospholipids was quantified for both strains. The fatty acid profile of the different lipid classes of these fungal strains was determined as a function of culture time.
Metabolism of Linoleic Acid or Mevalonate and 6-Pentyl-α-Pyrone Biosynthesis by Trichoderma Species
The understanding of the biosynthetic pathway of 6-pentyl-α-pyrone in Trichoderma species was achieved by using labelled linoleic acid or mevalonate as a tracer. Incubation of growing cultures of Trichoderma harzianum and T. viride with [U- 14 C]linoleic acid or [5- 14 C]sodium mevalonate revealed that both fungal strains were able to incorporate these labelled compounds (50 and 15%, respectively). Most intracellular radioactivity was found in the neutral lipid fraction. At the initial time of incubation, the radioactivity from [ 14 C]linoleic acid was incorporated into 6-pentyl-α-pyrone more rapidly than that from [ 14 C]mevalonate. No radioactivity incorporation was detected in 6-pentyl-…
Grape pulp, grape pips and their mixture: Novel substrates or supports for solid state fermentation
Grape marc, comprising of grape pulp and grape pips, is generated in high quantities during ethanol production, but has no significant commercial value. The components of the grape marc, individually or in combination, can serve as substrate or support in solid state fermentation. The potential benefits of sieved fractions (800-3150 µm particle size) was, therefore, evaluated using Trichoderma viride, with or whithout enrichment. Based on sorption isotherm profiles, grape pulp showed the best performance, though its ability to promote biomass formation was the lowest. The latter could be improved by enrichment with glucose. It, thus, offers potential as a reusable support. Grape pips promot…
Lipid accumulation inTrichodermaspecies
Two filamentous fungi, Trichoderma harzianum and Trichoderma viride, were compared for their ability to synthesize lipids on different carbon and nitrogen sources. Three culture media were selected for each strain after preliminary screening. All the test media were nitrogen-deficient (C/N = 60) so as to stimulate lipid accumulation. For both microorganisms the glucose-ammonium sulphate medium was the most conducive to lipid production: a lipid accumulation of 17% (w/w) of biomass dry weight was obtained for T. harzianum and of 32% (w/w) of biomass dry weight for T. viride. In sucrose-sodium nitrate medium T. harzianum was able to accumulate almost 25% (w/w) of its biomass in lipid form. Ho…
A simple protocol for extraction and detection of pyrazines produced by fungi in solid state fermentation
A protocol for the extraction and detection of pyrazines produced by fungi in Solid State Fermentation that gave good recovery of these compounds was devised together with specific techniques for detection by Gas Chromatography (GC). The protocol involved solid-liquid and liquid-liquid extractions, concentration of the extracts and GC analysis. Extraction yields were measured from a model system in which synthetic pyrazines were added. Extracts were analysed with a gas chromatograph equipped with a thermo-ionic detector to allow specific pyrazine detection.