Production of polysaccharidases by a
cellulase-pectinase hyperproducing
mutant (Po16) of Penicillium occitanis
S. Jain*, M. Parrichet, H. Durandt and G. Tiraby*
*Laboratoire de Microbiologie et G#n#tique appliqudes du C. N. R. S., C. R. B. G. C.,
Universit# Paul Sabatier, ?Laboratoire CA YLA, Toulouse, France
A new Penicillium strain characterized by high yields ofextracellular cellulase production, particularly
fl-glucosidase, was isolated from soil. On the basis of growth characteristics, reverse coloration, and
structure of Penicilli, this strain was assigned to a new species, named Penicillium occitanis. The
organism was subjected to a strain-improvement program, and a mutant (Pol6) was selected after
several rounds of mutagenesis with NTG, EMS, and UV. Selection was for strains that were resistant
to catabolite repression and were enhanced in cellulase and pectinase production. The strain Po16 was
also found to produce other polysaccharide-hydrolysing enzymes when grown on various inducing
substrates. The production of polysaccharidases by Penicillium occitanis strain Pol6, under various
fermentation conditions, and their preliminary separation by Fast Protein Liquid Chromatography is
discussed.
Keywords: Penicillium occitanis; Po16mutant; polysaccharidases;hydrolysis;mutagenesis;Fast Protein Liquid
Chromatography(FPLC)
Introduction
Bioconversion of cellulosic wastes to useful products
by enzymatic hydrolysis has been widely investigated
for several years. ~-3High yields of cellulases are known
to be produced by a few fungal genera, including Tri-
choderma, Sporotrichum (Phanerochaete), Fusarium,
Penicillium, and Talaromyces. The fungus Trichod-
erma reesei makes an active cellulolytic complex com-
prised of endo-l,4-fl-D-glucanases, exo-l,4-/3-D-cello-
biohydrolases, and /3-D-glucosidase, which acts
synergistically in the complete saccharification of cellu-
lose to glucose. 1'4 Unfortunately, T. reesei produces
only small amounts of/3-glucosidase,5 the enzyme re-
quired for the final conversion of cellobiose to glucose.
In contrast, P. funiculosurn produces high levels of
extramycelial fl-glucosidase, in addition to cellobiohy-
Addressreprintrequeststo Dr. Tiraby at the Laboratoire de Microbi-
ologie et G6n6tique appliqu6es du C. N. R. S., C. R. B. G. C.,
Universit~ Paul Sabatier, 118 route de Narbonne, 31062Toulouse
C6dex, France
Received 22 May 1989; revised 14 August 1989
drolase and endo 1,4-fl-glucanases. 6 Furthermore, mu-
tant strains of both P. funiculosum and P. pinophilum 7
have been developed for enhanced cellulase and /3-
glucosidase production. However, complete hydroly-
sis of raw materials also requires other polysacchari-
dases such as xylanase, amylase, pectinase, and/3-1,3-
glucanase.
A new strain of Penicillum named P. occitanis was
isolated from soil on the basis of its ability to produce
large amounts of cellulases. This isolate is attractive
because filtrates of cellulose-grown cultures have cot-
ton-hydrolysing activities as high as those of T. reesei
QM9414 and/3-glucosidase activities which are much
higher) The isolate also produces a broad spectrum of
polysaccharide-hydrolysing enzymes, which could be
useful in the complete hydrolysis of complex raw sub-
strates.
The present study reports the isolation of a hyperse-
creting mutant (Po16) ofPenicilliurn occitanis after mul-
tiple-step mutagenesis and the production of polysac-
charidases by this mutant when it is cultivated under
various fermentation conditions. Anion-exchange
chromatography was used for the preliminary separa-
tion of the extracellular proteins.
© 1990 Butterworth-Heineman Enzyme Microb. Technol., 1990, vol. 12, September 691