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Computers and Chemical Engineering Supplement (1999) S439-5442
(;) 1999 Elsevier Science Ltd. AIl rights reserved
PH: 50098·1354 /99/00176-3

Pergamon

Bioreactor model of the mushroom growth production process and its computer aided
simulation
*Zs. Viczian, **E. Laszlo, ***Zs. Fustos
Teclmical University of Budapest, Faculty of Chemical Engineering, Gellert ter 4., Budapest,Hungary, H-IIII
*Department of Chemical Informatics vzsolt.kit@chem.bme.hu; **Department of Agricultural Chemical
Technology; **Budapest University of Horticulture and Food Industry, Postharvest Department
Abstract
Bioreactors are widely used for the production of different microorganism in biotechnology. Mathematical models
for different types of reactors are known, In our paper we will usethese models to simulate mushroom growth in an
industrial production process. Among other models we will use the mathematical model of living polymerization to
simulate the size distribution of mushroom.
Keywords: Bioreactor, Simulation of mushroom growth, Living polymerization

Introduction
The theory of modeling and simulation of different
growth processes is well covered in literature.These
processes range from living polymerization to the
production of microorganism in bioreactors. At the
same time, not much can be read about the modeling
of more complex organisms such as mushrooms,
plants, not to mention animals. The reason can be
found in the number of parameters unknown or uncontrollable.
At the same time quality assurance and quality control in the agricultural and foodindustry is becoming
more and more a relevant issue. To implement such a
control or assurance system mod eling of the production procedure is needed.

In this paper we discuss some of the different possible
models applicable to the mushroom production procedure.
Material and method
The material of our
research was the mushroom grO\\TI by the
Biofungi Ltd.. At the
production unit inBudapest the Biofungi Ltd.
implements
underground
(basement)
production in a tunnel
Figure 2. A growing chamber system in large chamwith climate control sys. lip top bers.
All five mentioned climate parameters are controlled, and their
changes are recorded daily.
In our calculations we used the followin g measured data:
The weight of harvested mushroom in percent relative to
the weight ofcompost used.
The prescribed and the recorded climate parameters.
The measured cap sizes of mushrooms.
Our method basically included three steps. Displaying
measured data on different diagrams, testing possible
models to best fit the measured results. Finally explanation of the variables used by the models.
Exponential model of growth Pearl and Reed

Figure J. Picture inside a growingchamber at the
Biofungi Ltd. in Budapest, HUNGARY
From the above mentioned complex organisms,
mushroom production has the least amount of influencing parameters. It is produced following strict
climate control, where controlled parameters include
compost and air temperature, CO 2 concentration,
watering and relative humidity.

The first model we tried was that described by Pearl and
Reed. Thismodel basically uses the following equation
to describe the life of a population (Raymond Pearl,
1925):

(1)

1

N=--ke- rt +b

After becoming familiar with the exact production procedure we found that this model is not suitable to describe

Computers and Chemical Engineering Supplement (1999) S439-S442

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some important basic features of the production of
mushrooms. One ofthe important problems is the
following. If this model is used to describe an entire
population of mushrooms, than it can give approximation to the alI together produced mass of mushroom but leaves the question of size distribution
unanswered. At the same time the price of the fmal
product highly depends on its size. Mushrooms too
smalI or too large can only be sold for a lower price.
This...