Background: The potential of microwave-assisted heating for enhancing the alkaline pretreatment
of lignocellulosic waste is highlighted in this work.
Objective: To maximize separation of fermentable sugars from wheat straw.
Methods: Wheat straw hydrolysis assisted by microwave was carried out by setting up a statistical experimental
design method and further investigating the main process parameters, namely: temperature
(°C), microwave power (W), NaOH concentration (M) and wheat straw pre-treatment time (min) towards
maximization of fermentable sugars extraction from wheat straw. The reducing sugars yield (response)
of the alkaline pre-treated and microwaved wheat straw in lab scale provided data for building
a predictive model which reflected interactions, significance and impact of the process parameters
(factors) on the wheat straw hydrolysis yield.
Results: SEM and FTIR images of untreated and alkaline pre-treated wheat straw were studied for investigating
the morphological changes of wheat straw surface quality and structure resulting from the
microwave and/or alkaline pre-treatment. In addition reducing sugars yield of 87%wt. from wheat
straw pre-treated at 180°C, 550W microwave power, 0.65M of NaOH for 25min was achieved. This
result was significantly higher compared to the one from the straw which was only hydrolysed enzymatically
Conclusion: It was found that shorter pre-treatment times were obtained at higher temperatures, alkali
concentration and moderate microwave power levels. The results obtained were further optimized and
indicated that the microwave-assisted alkaline pre-treatment of wheat straw technique is an attractive
pre-treatment method which reduces the wheat straw pre-treatment time and enhances the hydrolysis