Title
Surfactant-assisted microwave-acid pretreatment of leaf litter biomass for enhanced enzymatic release of sugars
Authors
NADEEM AKHTAR KANIKA ALOK KUMAR JAIN DINESH GOYAL and ARUN GOYAL

Received December 2, 2014
Published Volume 50 Issue 1 January
Keywords hydrolysis, leaf litter biomass, microwave, pretreatment, surfactant

Abstract
Leaf litter biomass from Eucalyptus globulus was pretreated using a novel surfactant assisted microwave-acid pretreatment (SAMAP) technique for enhanced enzymatic release of sugars. Screening of the parameters for the SAMAP technique was carried out using the Taguchi experimental design, followed by enzymatic saccharification. The critical parameters identified were time, acid concentration and surfactant concentration. To optimize the saccharification of SAMAP biomass, the combined effects of the significant parameters were further investigated using response surface methodology (RSM). As compared to the reducing sugar yield of 0.05 g/g in native biomass, enzymatic hydrolysis of the recovered solid fraction of SAMAP biomass (0.5 mm) showed a 93% increase in reducing sugar (0.69 g/g), when treated with 1.25% H2SO4 and 0.2% Tween-80 followed by 80 FPU/g of enzymatic hydrolysis for 42 h. The composition of native biomass was 31% cellulose, 18% hemicellulose and 12% total lignin. Delignified SAMAP biomass after recovery showed a 33% increase in cellulose content, whereas hemicellulose and lignin content was reduced by 39 and 66%, respectively. Native and pretreated biomass was characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) and solid state 13C cross polarizing magic angle spinning (CP/MAS) NMR spectroscopy.