15 Fungi Involved in the Biodeterioration and Bioconversion of
Lignocellulose Substrates
BARRY GOODELL
1
CONTENTS
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
II. Wood Decay Fungi: Basidiomycota Decay
and Ascomycota Soft Rot Decay . . . . . . . . . . . . . . 372
A. Introduction to Decay Types . . . . . . . . . . . . . . . 372
B. Brown Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
C. White Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
D. Soft Rot/Ascomycota Fungi . . . . . . . . . . . . . . . . 384
III. Staining and Mold Fungal Degradation of
Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
A. Mold Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
B. Staining of Wood by Fungi . . . . . . . . . . . . . . . . . 386
IV. Biotechnological Applications of Decay
Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
A. White Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
B. Brown Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
V. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
I. Introduction
Fungi that cause deterioration of wood are primarily filamentous in form, and the body of the
fungus consists of fine (2–10 mM), hair-like,
elongated cells that branch and connect end to
end to form an interconnected network
(Schmidt 2006). Individual strands of the fungus are known as hyphae, whereas when
hyphae grow together in layers on the surface
of wood, they are called mycelia or a mycelial
matt. Mycelia can also form unique structures
such as sporophores (fruiting bodies) in
sexually-capable fungi. These fruiting bodies
may take the form of cups or discs in some
Ascomycota species, while in the Basidiomycota, mushrooms or bracket structures on the
side of wood substrates are common. Common/
colloquial names for the sporophores of Basidiomycota growing from wood include conks,
punks, shelf fungi, and others.
Mold fungi, stain fungi, soft rots, brown
rots, and white rots are the groupings typically
used for fungi that cause different types of
wood degradation. Mold fungi are generally
found in the Ascomycota. Traditionally many
of the mold fungi were classified as fungi
imperfecti or Deuteromycetes (not a formal
taxa), and as time has progressed with new
molecular techniques, many of these fungi
have been able to be classified as either Ascomycota or Basidiomycota. As will be discussed
later, mold fungi do not penetrate wood surfaces more than one or two cells, and they do
not metabolize structural wood components.
Because mold fungi do not degrade cellulose,
lignin, or hemicellulose to an appreciable
extent, they also do not cause appreciable
mass loss as mold infection advances.
Stain fungi are able to penetrate into the
sapwood of wood and sometimes living trees,
and they feed on the sugars and starches primarily found in the parenchyma cells. They
often initiate on the surface of wood, and in
that regard in early staining stages, the boundaries between these two types of fungi are
blurred, and stain fungi can be confused with
mold fungi. Although not common, some fungal species classified generally as stain fungi
have also been found to attack the structural
components of wood (Encinas and Daniel
1996). In general, however, stain fungi cause
only limited mass loss and cause only limited
structural damage to wood (Zabel and Morrell
2020).
1 University of Massachusetts, Amherst, MA, USA; e-mail:
bgoodell@umass.edu
Genetics and Biotechnology, 3 rd Edition
The Mycota II
J.P. Benz, K. Schipper (Eds.)
© Springer Nature Switzerland AG 2020
Lignocellulose Substrates
BARRY GOODELL
1
CONTENTS
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
II. Wood Decay Fungi: Basidiomycota Decay
and Ascomycota Soft Rot Decay . . . . . . . . . . . . . . 372
A. Introduction to Decay Types . . . . . . . . . . . . . . . 372
B. Brown Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
C. White Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
D. Soft Rot/Ascomycota Fungi . . . . . . . . . . . . . . . . 384
III. Staining and Mold Fungal Degradation of
Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
A. Mold Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
B. Staining of Wood by Fungi . . . . . . . . . . . . . . . . . 386
IV. Biotechnological Applications of Decay
Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
A. White Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
B. Brown Rot Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
V. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
I. Introduction
Fungi that cause deterioration of wood are primarily filamentous in form, and the body of the
fungus consists of fine (2–10 mM), hair-like,
elongated cells that branch and connect end to
end to form an interconnected network
(Schmidt 2006). Individual strands of the fungus are known as hyphae, whereas when
hyphae grow together in layers on the surface
of wood, they are called mycelia or a mycelial
matt. Mycelia can also form unique structures
such as sporophores (fruiting bodies) in
sexually-capable fungi. These fruiting bodies
may take the form of cups or discs in some
Ascomycota species, while in the Basidiomycota, mushrooms or bracket structures on the
side of wood substrates are common. Common/
colloquial names for the sporophores of Basidiomycota growing from wood include conks,
punks, shelf fungi, and others.
Mold fungi, stain fungi, soft rots, brown
rots, and white rots are the groupings typically
used for fungi that cause different types of
wood degradation. Mold fungi are generally
found in the Ascomycota. Traditionally many
of the mold fungi were classified as fungi
imperfecti or Deuteromycetes (not a formal
taxa), and as time has progressed with new
molecular techniques, many of these fungi
have been able to be classified as either Ascomycota or Basidiomycota. As will be discussed
later, mold fungi do not penetrate wood surfaces more than one or two cells, and they do
not metabolize structural wood components.
Because mold fungi do not degrade cellulose,
lignin, or hemicellulose to an appreciable
extent, they also do not cause appreciable
mass loss as mold infection advances.
Stain fungi are able to penetrate into the
sapwood of wood and sometimes living trees,
and they feed on the sugars and starches primarily found in the parenchyma cells. They
often initiate on the surface of wood, and in
that regard in early staining stages, the boundaries between these two types of fungi are
blurred, and stain fungi can be confused with
mold fungi. Although not common, some fungal species classified generally as stain fungi
have also been found to attack the structural
components of wood (Encinas and Daniel
1996). In general, however, stain fungi cause
only limited mass loss and cause only limited
structural damage to wood (Zabel and Morrell
2020).
1 University of Massachusetts, Amherst, MA, USA; e-mail:
bgoodell@umass.edu
Genetics and Biotechnology, 3 rd Edition
The Mycota II
J.P. Benz, K. Schipper (Eds.)
© Springer Nature Switzerland AG 2020