After microwave pre-treatment for 10 min, the WBY dosage of 10%, 15% and 20% led to almost similar reducing sugar yield 9.46%, 9.77%, 9.96% respectively, while 5% WBY gave a relatively lower reducing sugar yield of 8.63% (Fig. 1D). After 15 min pre- treatment, the four dosages reached their maximum values and the maximum reducing sugar yield increased with the dosage of WBY with values of 9.26%, 12.25% and 13.01% for 5%, 10% and 15% respectively, except for the dosage of 20%. In general the highest reducing sugar yield obtained from pre-treatment 4 was the lowest among the four pre-treatments.