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Title：Effect of co-cultivation of two Pleurotus species on lignocellulolytic enzyme
production and mushroom fructification
Speaker：馮怡菁
Moderator：洪家蕙
Date & Time：102.06.09 (日) 11:50-12:10
出場順序：9
一、
Introduction
Species of genus Pleurotus (Fr.) P. Kumm known as oyster mushrooms and they present
high adaptability to produce basidiomata within a wide variety of agro-industrial
lignocellulosic wastes due to their production of ligninolytic and hydrolytic enzymes
(Mikiashvili et al., 2006).
Co-cultivation of fungi could imply oxidative stress on both fungal partners, and it may
accelerate a fungal metabolic switch to secondary metabolism, thus stimulating wood decay
and production of lignin-degrading enzymes (Chi et al., 2007).Experimental evidence suggests
that the competition for space and nutrients may result in enhanced degradation of lignin
(Sundman and Näse, 1972; Asiegbu et al., 1996; Watanabe et al., 2003; Chi et al., 2007) and in
elevated production of lignin modifying enzymes, such as laccase (Freitag and Morrell, 1992;
White and Boddy, 1992; Score et al., 1997; Iakovlev and Stenlid, 2000; Baldrian, 2004; Chi et
al., 2007).
二、
Materials and methods
2.1 Strains
Pleurotus sapidus：BRAZIL,ICFC 631/05 ,Pleurotus sajor-caju,ARGENTINA,ICFC632/05 ,
Pleurotus ostreatus,BRAZIL,ICFC 688/06, Pleurotus djamor,AUSTRIA,ICFC 376/00 ,
Pleurotus ostreatus,ARGENTINA,ICFC 153/99, Pleurotus citrinopileatus,
ARGENTINA,ICFC 707/06 .above six strains selection colony were grown on MEA
Incubation was carried out at 25℃,and mycelial growth was measured.
2.2 co-cultivation patterns
Monocultures of P. ostreatus (PO) and P. citrinopileatus (PC) were assayed as well as dual
cultures with three different spatial patterns: Pattern 1) co-cultivation of P. ostreatus in the
upper portion of the bag and P. citrinopileatus in the bottom part of the bag (PO/PC); Pattern 2)
co-cultivation of P. citrinopileatus in the upper portion of the bag and P. ostreatus in the
bottom part of the bag (PC/ PO); Pattern 3) a mix of spawn from P. ostreatus and P.
citrinopileatus scattered in each bag (PC+PO) .Bags were transferred to the controlled room at
18-20℃,75%-85% humidity.Two flushes were collected during the cropping period [defined
as the time elapsed between the induction day and the last harvest day 120 days]. Mature
basidiomata were collected and the following production and quality traits were registered:
A)Production (harvested basidiomata); B) Primordia initiation (in days from the start of
incubation); C) Biological efficiency (BE): the ratio of kg of fresh mushrooms harvested per
kg of dry substrate and expressed as a percentage; D) Morphological quality traits: i) Pileus
width and length; ii) Stem length and diameter.
2.3 sample production
Samples of substrates colonized by mycelium were collected at three different stages of the
solid-state fermentation: T1 (30 d),after complete colonization of the substrate; T2 (43-64 d),
after the end of first flush; T3 (120 d), spent substrate after the last mushroom harvest. Entire
solid cultures were dried at 90 C, until constant weight, ground in a mortar, and stored until
they were used for chitin 、lignin determination and enzyme activities(laccase、Manganese
peroxidase activity、Endoglucanase、Endoxylanase、β-Glucosidase、β-Xylosidase).
三、
Results and discussion
P. ostreatus and P. citrinopileatus were selected for dual cultures because their similar growth
rates and their distinctive basidiomata since the former produced yellowish fruiting body.
The highest BE was obtained with the spatial pattern in which P. ostreatus was inoculated
in the upper part of the bag (PO/PC: BE% 103.7), but not significant differences (p≤0.05) were
found with monocultures of P. ostreatus (PO: BE% 95.3).
When total basidiomata production was analyzed on the basis of the total dry weight per bag
(300 g), we found that P. ostreatus production was significantly higher than the obtained with
monocultures of P. citrinopileatus and higher than any other treatment. In all co-cultivation
combinations yields were reduced being the mixed cultures (PO+PC) significantly lower (p≤
0.05) than any other assayed condition.
The co-cultivation of these species did not influence primordial initiation time, which lasted
from 43 to 50 days. Only the mixture pattern (PO+PC) lasted from 51 to 58 days. Regarding
morphological quality traits studied, both species decreased their stem’s length significantly
and P. ostreatus. produced shorter and narrower stems than in monocultures.
Different spatial patterns affected not only enzyme production but also mycelial yield.
Cellulolytic and xylanolytic activities detected increased significantly when P. ostreatus was
inoculated in the upper portion of the bag and P. citrinopileatus in the bottom part, highest
activities achieved were: endoglucanase 0.32, β -glucosidase 411.31, endoxylanase 0.27 and β
-xylosidase 50.40 U g-1 dry substrate. In coincidence, the highest BE was obtained with this
co-cultivation pattern (PO/PC: BE% 103.7).
四、
Conclusions
Spatial patterns influenced not only enzyme production but also basidiomata yield.
Although pileus morphology was not affected, stem lengthwas reduced in co-cultivation which
is more convenient for mushroomfarmers. Cellulolytic and xylanolytic activities detected
increased significantly when P. ostreatus was inoculated in the upper portion of the bag and P.
citrinopileatus in the bottom part, but co-cultivation did not stimulate ligninolytic enzyme
production. The highest laccase and Mn-peroxidase activities were detected in monocultures of
P. ostreatus, in coincidence with maximum lignin degradation.
五、
參考文獻
Maira Carabajal a, Laura Levin a, Edgardo Albertó b, Bernardo Lechner a,*.2012. Effect of
co-cultivation of two Pleurotus species on lignocellulolytic enzyme production and mushroom
fructification. International Biodeterioration & Biodegradation 66.71-76.