concentrations were 80–110% of corresponding 24 h concentrations. This indicates that despite statistical significance, additionaltime had a minor effect on the final lactate concentration, and led toa decrease in lactate concentration in some trials. Overall, batches1 and 2 indicated that optimum conditions were near 41◦C andpH 5.3 and at those optimum conditions, maximum concentrationcould be achieved between 16 and 24 h. Fig. 2c displays a near lin-ear relationship in lactate concentration with an increased loadingrate, indicating that loading rates above 150 g VS L−1could improve final concentration