Italian ryegrass (Lolium multiflorum Lam) as a High-Potential Bio-Ethanol Resource

Cellulosic bioethanol production from lignocellulosic biomass has been recognized as one of the promising sustainable energy source alternatives to petroleum-based fuels, since the lignocelluloses are not directly in competition with food sources. In order to develop a lignocellulosic raw material with high energy crops for bio-ethanol production, we selected Italian ryegrass (Lolium multiflorum Lam). Bio-ethanol production from Italian ryegrass through a low-moisture anhydrous ammonia (LMAA) pretreatment and simultaneous saccharification and co-fermentation (SSCF) was examined. At first, Italian ryegrass was subjected to LMAA pretreatment, which was performed by keeping the moist powdered Italian ryegrass under NH₃ gas atmosphere at room temperature for 4 weeks. The effect of LMAA pretreatment was examined for bio-ethanol production through simultaneous saccharification and fermentation (SSF) which was performed at 34 °C using Saccharomyces cerevisiae, cellulase, and xylanase. The yields of ethanol and xylose in SSF were enhanced by LMAA-pretreatment. The SSCF of the LMAA-retreated Italian ryegrass was performed at 36 °C using Escherichia coli KO11, S. cerevisiae, cellulase, and xylanase. The SSCF of LMAA-pretreated Italian ryegrass produced ethanol in higher yield (84.6 %) compared with those of LMAA-pretreated bamboo, rice straw, Napier grass, and silvergrass.