Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme III: PATHOGENS AND NUISANCES, FOOD AND MEDICINE Posters
Essential oils were incorporated at different concentrations
(0; 50; 100; 250; 500; 1000 ppm). Three isolates of each
species were inoculated and colony growth was
periodically measured for 21 days at two temperatures. At
sub-optimal concentrations, some essential oils were found
to stimulate growth. Ochratoxin production was modified
by the different treatments. Acknowledgement: This work
is part of the EU project 'Prevention of ochratoxin A in
cereals' (FAIR QLK1-CT-1999-00433).
814 - Degradation of lignocellulose by acellulolytic
strains (c-) of Pleurotus ostreatus
H. Camaño Heredia * , H. Leal Lara & R. Ramirez Carrillo
Department of Food Science and Biotechnology, Faculty of
Chemistry, National University of Mexico (UNAM), 04510
Ciudad Universitaria, Col Copilco, Mexico D.F., Mexico.
The main obstacle for bioutilization of lingocellulose byproducts
is lignin but It can be degraded by white-rot fungi
like the edible mushroom Pleurotus ostreatus. This fungus
is cultivated on agricultural and forestry wastes but wild
strains produce a simultaneous degradation of
polysaccharides and lignin. Acellulolytic strains (C-) of
Pleurotus ostreatus were bred from acellulolytic mutants to
promote a selective degradation of lignin. Commercial and
acellulolytic Pleurotus sp. strains were cultivated on a
commercial substrate prepared with fermented straw.
Changes in substrate composition were followed during the
whole production cycle. Lignin, glucan, xylan and ash
content were determined at spawning (t=0), at the end of
the incubation period (t=1) and after the first flush of
mushrooms (t=2) Ash content in substrate increased with
all strains when substrate was fully invaded and after the
first crop of mushrooms indicating substrate degradation.
Highly significant differences in lignin, glucan and xylan
degradation were observed. Acellulolytic strains (C-)
produced a larger degradation than commercial strains.
However, acellulolytic strain 71x512(C-) showed identical
lignin and xylan degradation as commercial strain K8501
and its glucan degradation was also identical to that of
another commercial strain, K1508. Remarkably, it was
observed with all strains that production of mushrooms
increases as xylan degradation decreases.
815 - Virulence of soil borne pathogenic fungi isolated
from forest areas and nurseries in north of Scotland on
scots pine and common alder
D. Chavarriaga * & S. Woodward
University of Abedeen, Department of Agriculture &
Forestry, MacRobert Building, 581 King Street, Aberdeen
AB24 5UA, Scotland, U.K. - E-mail:
d.chavarriaga@abdn.ac.uk
Soil borne fungi isolated from forest areas and nurseries in
North east of Scotland using baiting techniques, were
identified using classical taxonomy and molecular methods
(PCR amplification of ribosomal ITS regions; restriction
digestion; sequencing of PCR products) as Fusarium
lateritium, Fusarium tricinctum, Phytophthora cinnamomi,
Pythium ultimum var. ultimum and Rhizoctonia binucleate
(Ceratobasidium sp.). Virulence was tested in vitro on
young seedlings of Pinus sylvestris and Alnus glutinosa,
and Koch's postulates fulfilled through reisolation of the
pathogens and confirmation of fungal penetration into host
tissues. Root growth was measured using the Winrhizo
program, and dry weights recorded. Symptoms on aerial
parts were assessed 8, 12 and 48 days after inoculation
using a categorical scale from 0 (healthy) to 5 (damage >
76%). Fusarium spp. caused significantly different (P<
0.01) symptom intensity on both host plants. However, no
significant difference in root growth was found between
treatments and control (P < 0.05). Highest mean root
length, numbers of root tips and forks, volume and surface
area on Alnus glutinosa occurred in plants inoculated with
P. cinnamomi and Pythium ultimum.
816 - Antifungal activity of natural antimicrobial
compounds incorporated in to cyclodextrin for slow
release in food packaging systems
D. Dorph-Petersen, K.I. Suhr & P.V. Nielsen *
Technical University of Denmark, Sølvtofts plads,DK-2800
Lyngby, Denmark. - E-mail: pvn@Biocentrum.dtu.dk
The antifungal effect of spices has been known for
centuries. Examples are the use of hobs in beer making and
the use of myrrh and thyme in mummification. Recently
attention on using essential oils from spices as
antimicrobial agent in food has grown. The effects of
essential oils are strongly depended on application method,
storage conditions, source and age of the oils and of course
on the microorganisms likely to colonise the food product.
In this research project we are investigating if antimicrobial
compounds from spices and herbs can be used in food
packaging systems either as a surface coat or integrated
into a film. These compounds are often too volatile and
insufficiently heat stable to be used directly. Incorporation
of these active compounds into cyclodextrin (CD) can
radically improve the heat stability of these compounds and
to some degree control their release into the packaging
atmosphere. We will here report our findings from studies
of antifungal effect of selected active agent from essential
oils incorporated into cyclodextrin, as compared to the
effect of the corresponding pure essential oils. The active
agents that were used were allyl-isothiocyanate (AITC)
from mustard oil, citral from lemongrass oil and thymol
from thyme oil. The moulds, Penicillium commune, P.
roqueforti and P. nalgiovense, all associated with cheese,
were used as test organisms.
Book of Abstracts 245