ABSTRACT
The present study investigates the operational conditions for organosolvent pretreatment and hydrolysis of rice straw. Among the different organic acids and organic solvents tested, acetone was found to be most effective based on the fermentable sugar yield. Optimization of process parameters for acetone pretreatment were carried out. The structural changes before and after pretreatment were investigated by scanning electron microscopy, X-ray diffraction and Fourier transform infrared (FTIR) analysis. The X-ray diffraction profile showed that the degree of crystallinity was higher for acetone pretreated biomass than that of the native. FTIR spectrum also exhibited significant difference between the native and pretreated samples. Under optimum pretreatment conditions 0.458 g of reducing sugar was produced per gram of pretreated biomass with a fermentation efficiency of 39%. Optimization of process parameters for hydrolysis such as biomass loading, enzyme loading, surfactant concentration and incubation time was done using Box-Benhken design. The results indicate that acetone pretreated rice straw can be used as a good feed stock for bioethanol production.
Subject(s)
Ethanol/metabolism , Oryza/metabolism , Solvents/pharmacology , Acetone/pharmacology , Biomass , Biotechnology , Fermentation/drug effects , Hydrolysis , Lignin/metabolism , Spectroscopy, Fourier Transform InfraredABSTRACT
The aim of this work was to study the feasibility of using sugarcane tops as feedstock for the production of bioethanol. The process involved the pretreatment using acid followed by enzymatic saccharification using cellulases and the process was optimized for various parameters such as biomass loading, enzyme loading, surfactant concentration and incubation time using Box-Behnken design. Under optimum hydrolysis conditions, 0.685 g/g of reducing sugar was produced per gram of pretreated biomass. The fermentation of the hydrolyzate using Saccharomyces cerevisae produced 11.365 g/L of bioethanol with an efficiency of about 50%. This is the first report on utilization of sugarcane tops for bioethanol production.
Subject(s)
Acids/chemistry , Biofuels , Carbohydrates/chemistry , Ethanol/chemistry , Saccharomyces cerevisiae/metabolism , Biomass , Biotechnology/methods , Cellulase/chemistry , Fermentation , Hydrolysis , Lignin/chemistry , Polysaccharides/chemistry , Saccharum/metabolism , Spectroscopy, Fourier Transform Infrared/methods , Surface-Active Agents/chemistryABSTRACT
In recent years, growing attention has been focused on the use of lignocellulosic biomass as a feedstock for the production of ethanol, a possible renewable alternative to fossil fuels. Several pretreatment processes have been developed for decreasing the biomass recalcitrance, but only a few of them seem to be promising. In this study, effect of various organic solvents and organic acids on the pretreatment of sugarcane bagasse was studied. Among the different organic acids and organic solvents tested, formic acid was found to be effective. Optimization of process parameters for formic acid pretreatment was carried out. The structural changes before and after pretreatment was investigated by scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The X-ray diffraction profile showed that the degree of crystallinity was more for pretreated biomass than that of untreated. The FTIR spectra shown at the stretching of hydrogen bonds of pretreated sugarcane bagasse arose at higher number. It also revealed that the cellulose content in the solid residue increased because the hemicelluloses fraction in raw materials was released by acid hydrolytic reaction.
Subject(s)
Biofuels , Cellulose/chemistry , Cellulose/metabolism , Ethanol/metabolism , Formates/chemistry , Saccharum/chemistry , Biomass , Cellulase/metabolism , Fermentation , Hydrolysis , Microscopy, Electron, Scanning , Spectroscopy, Fourier Transform Infrared , X-Ray DiffractionABSTRACT
India has a pressing need for renewable transportation fuels and bio-ethanol is considered as one of the most important options. Currently the country mandates use of 5% ethanol blending in motor gasoline in several states. The ethanol for this is mainly sourced from molasses feedstock, but this is barely sufficient to meet the current demand. Lignocellulosic biomass is the alternative but the availability of this resource is poorly documented. Also the technologies for ethanol production from lignocellulosic biomass are under preliminary stages of development which warrants extensive R&D in this field. The review discusses the current status of molasses based ethanol production in India and its limitations, the state of technologies for second generation ethanol production and the availability of feedstock for bio-ethanol production.