CHAPTER 4: TECHNOLOGY OF MUSHROOM
CULTIVATION
Synopsis
This Chapter deals with the principles and practices of gourmet
and medicinal mushroom cultivations. It stresses that
successful cultivation involves the interaction of scientific
knowledge and practical experience. Annual world production
of gourmet and medicinal mushrooms is now estimated in
excess of 14 billion US dollars. The operations essential to
successful cultivation involve: selection of mushroom spores
or strains, maintenance of mycelial cultures, development of
spawn or inoculum, preparation of growing medium, inoculation
and colonization, and crop management for optimum
production. However, for greater pharmaceutical acceptance it
is increasingly being recognized that product formation by way
of fermenter-grown mycelial biomass will be the preferred
option in many cases.
Introduction
Mushroom science is the discipline that is concerned with the principles and
practices of mushroom cultivation. As is true in any branch of science, it is essential
to establish the facts upon which principles can be derived for future developments of
the discipline. Consistent production of successful mushroom crops will be built upon
scientific knowledge and practical experience (Chang and Miles, 1989).
Rhere are at least 12,000 species of fungi that can be considered as
mushrooms with at least 2,000 species showing various degrees of edibility (Chang,
1999a). Furthermore, over 200 species of mushroom have been collected from the
wild and utilized for various traditional medical purposes mostly in the Far East. To
date, about 35 mushroom species have been cultivated commercially and of these,
about 20 are cultivated on an industrial scale (Table 1). The majority of these
cultivate species are both edible and possess medicinal properties. However, two of
the major medicinal mushrooms, viz. Ganoderma lucidum and Trametes (Coriolus)
65
spp. are distinctly inedible. Overall, the world production of cultivated edible and/or
medicinal mushrooms was recorded as 4,909.3 x 103
tons in 1994 increasing to
6,158.4 x 103
in 1997 with an estimated value in excess of 14 billion US dollars
(Chang, 1999b).
Mushroom cultivation is a worldwide practice (Table 2). In percentage terms,
output yield of the leading 10 species cultivated made up c 92% of total world
production of these six species, viz: Agaricus bisporus (31.8%); Lentinus edodes
(25.4%), Pleurotus spp. (14.2%), Auricularia auricula (7.9%), Flammulina velutipes
(4.6%), and Volvariella volvaceae (7.9%), made up 87% of the total production. It
can be further observed that by late 1994, of these six species only Agaricus and
Pleurotus were cultivated worldwide to be joined in 1997 by Lentinus. The other
three of the major six species are grown almost exclusively in Asia (Chang, 1999b).
World production of mushrooms over the last two decades has shown a
phenomenal pattern of growth (Table 1), with a 5 times increase in tonnage. While
the white button mushroom (Agaricus bisporus) still retains the highest overall world
production, its relative contribution is decreasing due to the dramatic increase in the
other species, viz: Lentinus and Pleurotus in particular. In 1981, Agaricus production
represented 72% of world production but by 1997 this had dropped to 32%. Overall,
world production of mushrooms is increasingly being dominated by species that are
both edible and have medicinal properties.