This experiment was conducted to study on single cell protein production from copra meal residue by Saccharomyces cerevisiae and Bacillus subtilis as animal feedstuffs. The experimental design was 4x3 factorial in CRD experiment with two factors were design to experiment. The first factor was comprised of fermented period (0 15 30 and 45 days). While the second factor B was comprised of microorganism type (Saccharomyces cerevisiae Bacillus subtilis and Saccharomyces cerevisiae combined with Bacillus subtilis). The results showed that interaction between factor A and B on pH (4.00-4.53) and percentage yield (29.21-33.80) were highly significantly different (P<0.01). However Incubation temperature were not related between factor A and B. Additional both factor have no effect to incubation temperature (P?0.05). For nutrients composition the group was fermented Saccharomyces cerevisiae combined with Bacillus subtilis showed higher Crude Protein than other treatments (P<0.01). Optimum of period at days 45 showed that crude protein 14.77 percent was significantly (P<0.01) and pepsin digestibility 66.60 percent was significantly (p<0.01)

During fermentation process yeast cells are often exposed to ethanol. Although the toxicity of ethanol to budding yeast Saccharomyces cerevisiae has widely been studied the ethanol stress signaling is still unknown. The growth of the mutants lacking genes involved in the mitogen activated protein kinase (MAPK) pathways was examined under ethanol stress condition. Our results revealed that the STE3 and AKR1 genes involved in the pheromone signaling pathway and the BCK1 MPK1 SWI4 SWI6 and MBP1 genes involved in the cell wall integrity pathway were required for tolerance to ethanol. In addition to the mutants of the cell wall integrity pathway the Δste3 and Δakr1 mutants were sensitive to a cell wall perturbing agent calcoflour white suggesting the role of these signaling molecules in maintaining cell wall during ethanol stress.

Heavy metal is one of the major environmental pollutants. However the protective cellular mechanisms in response to heavy metal stress are not well-understood yet. Previously it has been found that the yeast deletion mutants lacking vacuolar H+-ATPase (V-ATPase) activity which functions in vacuolar acidification exhibited growth defects under cadmium stress conditions. In addition several genes involved in H+-ATPase have been recently found to be required for resistance to aluminum. To investigate the roles of vacuolar H+-ATPase plasma membrane H+-ATPase and mitochondrial H+-ATPase in tolerance to cadmium we examined the growth of yeast deletion mutants lacking different types of H+-ATPase in YPD media containing 80 μM of cadmium. Our results showed that a number of mutants lacking V-ATPase activity were sensitive to cadmium suggesting the important role of V-ATPase in cadmium detoxification. We next examined the growth of mutants lacking genes responsible for different vacuolar functions in order to investigate the functional activities of vacuoles involved in cadmium detoxification mechanism. We found that the mutants lacking vacuolar protein-sorting genes exhibited high sensitivity to cadmium as well suggesting the importance of protein transportation during cadmium stress.