Figure 5
The effect of L -cysteine as a reducing agent on S. toebii growth. L-cysteine (0.025% final concentration) was added to 100 ml PEPN broth containing 0.2 mg ml-1 of the same CFE prepared from microaerobically, anaerobically or aerobically cultured G. toebii with the experiment of figure 4. S. toebii was cultured in a N2 gas-flushed anoxic cultivation system at 60°C. Squares, with CFE prepared from aerobically cultured G. toebii; diamonds, with CFE prepared from microaerobically cultured G. toebii; circles, with CFE prepared from anaerobically cultured G. toebii; triangles, without CFE (as a negative control, N.C.). S. toebii growth was monitored by measuring accumulated nitrite in culture broth.