Dry processing of lignocellulose biomass into ethanol and organic acids: A process innovation

Reduction of processing cost of lignocellulose bioconversion to a profitable level is crucially important for shaping the future industry of cellulose based biofuels and biochemicals production. Currently, the cost of cellulosic ethanol is still greater than the acceptable market range because of the severe technical barriers of lignocellulose bioconversion. The high production cost of cellulosic ethanol was affected by many factors such as expensive cellulase enzymes, low ethanol yield from cellulose and hemicellulose, high energy consumption, and high waste water treatment cost. Among these factors, the high energy consumption and waste water generation from lignocellulose bioconversion contributed a large percentage to the processing cost in industrial scale plants. In this talk, a processing innovation study was demonstrated for overcoming the two drawbacks. A dry processing strategy of lignocellulose for ethanol and organic acid production was proposed. This process started from the handling of raw lignocellulosic materials, followed by a series of “dry” processing operations including the dry dilute acid pretreatment, the solid state biodetoxification, and the simultaneous saccharification and fermentation (SSF) at high solids loading. The waste water generation and energy consumption were significantly reduced. The high product titer and yield close to the advanced starch based processes was obtained. The process provided a new idea of lignocellulose processing, and may serve as the technology basis for large scale productions of ethanol and organic acids from lignocellulose. Several industrial demonstration plants were under the development and constructions.