467 M (t) P Rm t e (mL-H2/Lsubstrate (mL-CH4/Lsubstrate (mL-H2/Lsubstrate (mL-CH4/Lsubstrate (mL-H2/L·h (mL-CH4/L·h Lag time (h) h) 2.71828 9 sp KKU-PS1 mL-H2/L Modified Gompertz SigmaPlot® Lag time