Studies On Ethanol Production From Water Hyacinth And The Residue Of Liquorice

The water hyacinth and the resid ue of liq uorice which increased suddenly in recentyears are the cellulosic waste.Their bulk depositions not only polluted the environmentand destroyed the ecological bala nce but also made a waste of resources.This thesisstudied the fuel ethanol production process from them. The ma in find ings are as follows:On the basis of the study of their constituents,different methods of acid pretreatmentsor base pretreatments were used to pretreat them firstly. The results indica ted that acidpretreatment is better for water hyacinth while base pretreatment is better for the resid ue ofliq uorice .The optimization experiments proved that the best acid pretreatment conditionsfor water hyacinth is using 0.25% H2SO4 to react 60min at 100℃in a solid-liq uid ratio of1:10. Under this condition, the reducing sugars conversion rate of water hyacinth is21.40%. The best base pretreatment conditions for the resid ue of liq uorice is using1%NaOH to react 90 min at 25℃in a solid-liq uid ratio of 1:10 at which the reducingsugars conversion rate is 37.55%.In order to reduce costs and environmental pollution, white- & brown-rot fungipretreatments were used to pretreat them. The most effective method for water hyacinth isto pretreat by Antrodia monicda 5898 or Fomitopsis sp.IMER2 for 10 days；or byEchinodontium taxodii 2538 for 20 days. For the resid ue of liq uorice , the most effectivebiologica l pretreatment is to pretreat by Auricularia polytricha for 15 days. After thefungal pretreatment, The reducing sugars conversion rate of bio-pretreatment is highertha n that of 0.25% H2SO4 only.On the basis of the previous study, chemica l pretreatments and fungal pretreatmentswere combined to get a better result. The optimization experiments proved that the mosteffective pretreatment for water hyacinth is using Echinodontium taxodii 2538 to pretreat10 days first, and then using 0.25% H2SO4 to react 60min at 100℃in a solid-liq uid ratioof 1:10. Under this condition, the reducing sugars conversion rate is 11.7% higher tha n thatobtained without fungal pretreatment. The most effective pretreatment for the resid ue ofliq uorice is using Auricularia polytricha to pretreat 15 days first,and then using 0.4%NaOH to react 2h at 40℃in a solid-liq uid ratio of 1:10.At last, the simultaneous saccharifica tion and fermentation (SSF) of waterhyacinthand the resid ue of liq uorice pretreated with fungi-chemica ls was studied. The results proved that 0.8% inoculum size, 30 g/L substrate, pH 4 for 96 hours could be the mosteffective way for water hyacinth, under which the yields of ethona l achieved 0.06 g/g. Theethanol yield of water hyacinth pretreated with fungi-chemica ls was 15.4% higher tha nthat of the single chemica l pretreatment under the best fermention conditions.The bestcondition for the fungal-chemica l pretreated resid ue of liq uorice was 50 FPU/g cellulaseload ing, 30 g/L substrate, pH 3 for 24 hours. Compared to the single chemica l pretreatedones, the amount of ehanol obtained increased by 7.3%.The results above present a new economic way of ethona l production. It is not onlymea mingful in socia lization but also makes cellulosic waste renewable.