ISOLATION, PURIFICATION AND SOME PROPERTIES - Biochemistry and Biotechnology: Research and Development - page 12

Figure 4. Influence of the temperature on LO synthesis by Trichoderma sp . 6 in bioreactors. рО 2 -70-
80%, рН - without adjustment. a-LO activity; b- рН. -37 о С; 2. -29 о С; 3. -24 о С.

Microphotographs of Trichodеrma sp. 6, grown on wheat bran by solid phase
fermentation (A) and bulk cultivation (B) are presented in Figure 2. The morphological
properties of this strain are similar with the strains T. viride Y244-2 and IFO 4847, capable to
synthesize LO [8], but not so intensively as the original strain Trichodеrma sp. 6, which was
found in the present work.

Table 1. Synthesis of extra cellular L-lysine -oxidase (U/g of wheat bran)*
by Trichodermа fungi during solid-phase cultivation. Influence of different nitrogen
sources (4%)

Nitrogen sources
-

Strain

NaNO 3 КNO 3 (NH 4 ) 2 SO 4 NH 4 Н 2 РО 4 NH 4 NO 3

T. aureoviride
Rifai VKM F-
2026

2 15 10 10 10 20

T. viride Pers.
VKM F-2721

3 20 10 15 10 30

T.
longibrachiatum
Rifai ВКМ F-
2025

2 10 10 5 5 15

Trichoderma sp . 6 5 30 20 20 15 50

*Maximal activity observed during cultivation on the 12-13 day.

As Trichodermа sp. 6 afforded to obtain the highest yield of LO during the solid-phase
and bulk cultivation in the flasks, this strain was chosen for LO biosynthesis in large scales.
The influence of aeration on LO biosynthesis was studied in 3-l bioreactors. The cultivation
was carried out in the medium containing 6% NH 4 NO 3, at 29 о С without pH correction. The
most active LO biosynthesis - 8.5 U/ml (120 U/g of wheat bran) occurred at рО 2 70-80% of
saturation (Figure 3, curve 1). At lower рО 2 the LO biosynthesis was not so high (curves 2, 3)
probably because this levels of oxygen were insufficient for biomass growth. Figure 4. shows
the influence of temperature on LO biosynthesis at controlled рО 2 =70-80% of the saturation.