Abstract:
In the recent years, bioethanol derived from lignocelluloses biomass as an alternative
to the conventional fuels is becoming a focus of many researchers. In this study,
bamboo (BM) is used as a feedstock for the production of total reducing sugars via
alkaline pretreatment, enzymatic, and acid hydrolysis process. Specifically, the focus is
mainly on the investigation of the effect of alkaline pretreatment on the yield of total
reducing sugar from bamboo (yushania alpine) biomass using sodium hydroxide as a
catalyst. Alkali concentration, pretreatment temperature, and time were varied in the
alkali pretreatment experiments. Following the pretreatment, enzymatic, and dilute
sulfuric acid hydrolysis of the pretreated bamboo were carried out for the comparison
of total reducing sugar yields. The raw and pretreated bamboo was characterized for
their composition using NREL and ASTM protocols. The total reducing sugar
concentrations after hydrolysis were determined by DNSA method. It is found that, the
raw bamboo has a composition of 42.45 % cellulose, 23.6 % hemicelluloses, and 32.4%
Lignin. The alkali pretreatment resulted in a maximum lignin removal of 35.5% at
temperature of 60oC, contact time of 50 min, and alkali concentration of 4.5% w/v,
which leads to an increment of cellulose fraction to 64.93% and reduction of lignin
20.8%. A maximum total reducing sugar yield of 206.3 mg/g and 351.9 mg/g were
obtained for pretreated bamboo by using enzymatic (endoglucanase and β-glucosidase)
and dilute sulfuric acid hydrolysis, respectively. Within the ranges of pretreatment
conditions considered, increasing temperature, reaction time, and alkaline
concentration favor the percent lignin removal and this increases total reducing sugar
yields