This indicates that there is a positive interaction between L. fermentum 04BBA19 and S cerevisiae.

The rise of the both microbial population means that there is mutualism between L. fermentum 04BBA19 and S. cerevisiae. Mutualism defines the relationship in which some reciprocal benefit accrues to both partners [18]. Mutualism between S. cerevisiae and L. fermentum 04BBA19 could be explained by the fact that the amylolytic lactic acid bacterium strain L. fermentum through its amylase activity releases the glucose necessary for Talazoparib cell line the growth of yeast. The yeast S. cerevisiae in turn stimulates amylase activity in L.fermentum by consuming a portion of the glucose produced, thus reducing any excess glucose. The excess glucose is generally recognized as a repressor of the enzyme synthesis in many bacteria [10]. The analysis of variance (ANOVA) of growth parameters (μmax and lag) of mixed culture I showed that for B. amyloliquefaciens 04BBA15, there was no significant differences (P < 0.05) between these parameters in pure and mixed culture ( Table 3), while for S. cerevisiae, significant changes (P < 0.05) in growth parameters were observed when both strains

were grown together, thus confirming the occurrence of an interaction between the two microorganisms. On the other hand the kinetic parameters varied with temperature, the maximum of interaction between S. cereviae and Cyclopamine cell line B. amyloliquefaciens RG7420 nmr 04BBA15 was achieved at 35 °C ( Table 3). At this temperature, the specific maximum growth rate of S cerevisiae increased considerably and reached 0.450 h−1. An important reduction of lag time was observed and the logcount of S. cerevisiae reached maximum value (12.0), indicating that temperature was an important environmental factor affecting the interaction between both microorganisms. The ANOVA of growth parameters of mixed

culture II (Table 4) also showed significant differences (P < 0.05) for all the growth parameters when passing from pure to mixed culture. This significant change confirmed the existence of positive interaction between L. fermentum 04BBA19 and S. cerevisiae. In monoculture fermentation (pure culture), the level of amylase production increased and reached maximum value after 40–50 h of incubation at 30 °C, 107.5 ± 0.5 U mL−1 and 147.5 ± 0.3 U mL−1 respectively for B. amyloliquefaciens 04BBA15 and L. fermentum 04BBA19. When each of these cultures was associated with S. cerevisiae, a significant increase in α-amylase production was observed in the culture medium ( Fig. 3). The duration for maximal amylase production (30 h) was less than that observed in pure culture. The levels of amylase production were 300.0 ± 0.3 U mL−1 and 351.1 ± 0.4 U mL−1 respectively for B. amyloliquefaciens 04BBA15and L. fermentum 04BBA19 ( Fig. 3). The presence in the culture medium of S. cerevisiae stimulated and enhanced α-amylase synthesis by both amylase producing bacteria.