Hydrothermal microwave processing for corn residues as a pretreatment for xylo-oligosaccharides production in a biorefinery concept

Hydrothermal microwave processing (HMP) has received attention due to its advantages in rapid reaction using lignocellulosic materials (e.g. corn residues). The xylo-oligosaccharides (XOS) are interesting raw material for bioethanol production, chemicals, pharmaceutical and biomaterials industry in a biorefinery concept. The production of XOS from hemicellulose fraction using HMP has been studied in work. The HMP was evaluated in different conditions of solid-liquid ratio (w/v), time (10, 30 and 50 min) and temperature (150, 165 and 180 ºC) and based on the utilization of water catalyst, causing an autohydrolysis process.  Thus, water was added to corn residues and placed in a pressurized reactor, this reactor was operated in isothermal heating regimen. The heating was performed by microwave process, which drastically reduces heating times and the degradation of the hemicellulose fraction. The highest production of XOS was 10.39 g/100 g of raw material at 180 ºC/ 10 min with a liquid–solid ratio of 1/20 (v/w), with a severity factor of 3.35. This research evidenced that HMP is an interesting alternative for add value of corn residues compounds being in accordance with the biorefinery concept.