interactions and mannan-degrading enzyme activities from
fungal mixed cultures grown on palm kernel cake
F. B. Iluyemi1
and M. M. Hanafi2*
of Land Management, Faculty of Agriculture, Universiti Putra
Malaysia 43400-UPM, Serdang, Selangor, Malaysia.
of Tropical Agriculture, Universiti Putra Malaysia
43400-UPM, Serdang, Selangor, Malaysia.
*Corresponding author. E-mail:
firstname.lastname@example.org. Tel: +603-89467842.
23 April, 2009
kernel cake (PKC), a by-product of the palm kernel oil
extraction process contains mannan as its main
polysaccharide. Mixed culture microbial degradation may
enhance mannan-degrading enzymes production. Therefore, the
objective of the study was to examine the nature of mycelial
interactions and corresponding production of mannan-degrading
enzymes of PKC. Fungal interactions was carried out using
Sclerotium rolfsii and Aspergillus niger co-cultured with three Trichoderma
strains (Trichoderma harzianum, Trichoderma
longiobrachiatum and Trichoderma koningii) on
potato dextrose agar (PDA) in disposable petri-dishes.
Measurements of growth diameters were taken on days 2 and
13. For mannan-degrading enzyme production, single and
co-cultures of these fungi were carried out under submerged
cultivation for 13 days with PKC as the carbon source. About
57% of observed interactions on PDA were deadlock, 29%
replacement and 14% intermingling. In Trichoderma
sp./A. niger mixed cultures, there was an
overall significant enhancement of enzyme: 2 to 200 fold (b-D-mannanase),
8 to 25 fold (b-mannosidase)
and from no change to 15 fold increase (a-galactosidase).
There was no obvious relationship between enzyme production
and protein yield. However, co-culturing of A. niger
with the Trichoderma strains showed an enhancement of
mannan-degrading enzyme activities without reducing biomass
fungi, co-cultures, palm kernel cake.