【摘要】 绝大多数现有的杜仲胶提取方法都需要将杜仲皮和杜仲叶粉碎,降低了杜仲胶的弹性、韧性、抗拉强度。为了获得长丝杜仲胶,研究了纤维素酶对杜仲纤维素细胞壁水解、杜仲叶表面的角质层的去除以及长丝杜仲胶的提取。发现1%氢氧化钠在70℃条件下能除去杜仲叶表面阻挡纤维素酶作用的角质层,石油醚是一种十分理想的提取杜仲胶的溶剂。纤维素酶在pH为4时,50℃条件下能充分地水解纤维素细胞壁,提高了细胞的通透性,使得石油醚(60～90℃)可溶解出高聚合度的长丝杜仲胶,并且使杜仲胶的回收率由原来的2.5%提高了3%以上,拉伸强度也由粉碎样的0.02MPa提高到60.5MPa,断裂伸长率由～0%提高到24%,撕裂强度由0.5kN/m提高到36kN/m。活性碳能很好地回收石油醚中所溶解的脂溶性天然化学成分,提高了溶剂循环使用的溶解能力。更多还原

【Abstract】 The current major methods for extracting Eucommia ulmoides gum require that Eucommia ulmoides leaf and bark be pulverized prior to gum extraction,which,hence,lead the elasticity,malleability and tensile strength to reduce.To extract long silk gutta percha,this paper investigated the hydrolysis of plant cell wall of Eucommia ulmoides by cellulase,the removal of cuticle layer on Eucommia ulmoides leaf and the extraction of long silk gum.It was found that 1% NaOH at 70 ℃ efficiently degraded the cuticle layer from E.ulmoides leaf,which prevented cellulase to touch and hydrolyze cell wall of fiber.Petroleum ether (60-90 ℃) is an ideal solvent to extract E.ulmoides gum.Cellulase hydrolyzed cellulose cell wall effectively at 50 ℃ and pH 4.Thus permeability of cell wall increased and E.ulmoides gum with long silk was easy to dissolve into petroleum ether and the yield increased from original 2.5% to over 3%.The tensile strength of obtained gutta percha increased from 0.02 MPa of milled E.ulmoides leaf to 60.5 MPa,breakage-extensibility from about 0% to 24% and tearing strength from 0.5 to 36 kN/m.Activated carbon can well adsorb nature compounds from E.ulmoides leaf and bark that dissolve in petroleum,promoting the dissolving capacity of used petroleum ether in recycle.更多还原