【作者】 曹秀华； 祁建民；

【Author】 Xiuhua Cao,Jianmin Qi~* (Key Laboratory of Ministry of Education for Genetics,Breeding and Multiple Utilization of Crops,Fujian Agriculture and Forestry University,Fuzhou,350002)

【机构】 福建农林大学作物遗传育种与综合利用省部共建教育部重点实验室；

【摘要】 红麻是一年生韧皮纤维作物,具有较高的生物质产量,其茎秆主要成分为纤维素、半纤维素、木质素、果胶等,经发酵可转化为酒精。本研究以红麻杆为原料,从自然界中分离筛选纤维素类降解菌、半纤维素降解菌、木质素降解菌、果胶降解菌及优化其降解条件,并对糖化工艺及发酵工艺进行了初步研究。获得如下结果:(1)纤维素降解菌的筛选及产酶条件优化。从腐烂的朽木及土壤采样,用划线分离法进行分离纯化,在刚果红培养基上进行初筛,筛选到18株纤维素降解菌:测CMC(羧甲基纤维素钠)酶活进行复筛,筛选出一株产纤维素酶活较高的菌株,对其产酶条件进行优化,获得最佳产酶条件为:在30℃、pH=6条件下培养,第6d酶活最高达198.06U/g。(2)半纤维素降解菌的筛选及产酶条件优化。从腐烂的朽木及土壤采样,用划线分离法进行分离纯化菌种,用双层平板法进行初筛,筛选到13株半纤维素降解菌;测半纤维素酶活进行复筛,筛选到一株产半纤维素酶活较高的菌株,并对其产酶条件进行优化,其最佳产酶条件为:在30℃、pH=5、PDA培养基中培养,第5d酶活最高达1013.88U/g。(3)果胶降解菌的筛选及产酶条件优化。从自然界中采样,用划线分离法进行分离纯化,用刚果红染色法进行初筛,筛选到16株果胶降解菌;测其酶活进行复筛,筛选到一株产半纤维素酶活较高的菌株,并对其产酶条件优化,其最佳产酶条件为:在30℃、pH=5、PDA培养基中培养,第5d酶活最高达322.21U/g。(4)木质素降解菌的筛选及产酶条件优化。从自然界中采样,用划线分离法进行分离纯化,用苯胺蓝法进行初筛,筛选到8株木质素降解菌;测漆酶酶活后进行复筛,筛选到一株木质素高效降解菌,对其产酶条件进行优化,其最佳产酶条件为:在30℃、pH=5、PDA培养基中培养,第8d漆酶酶活达294.81U/g。(5)预处理方法的研究。对红麻秸秆采用蒸汽爆破、稀硫酸、浓硫酸、NaOH等方法进行预处理优化,其中以2%NaOH溶液进行预处理最佳。(6)糖化工艺的研究。糖化曲与2%NaOH预处理的红麻秸秆粉进行作用,对糖化曲的作用条件进行优化,其最佳条件为:在55℃、pH=5.0、酶解时间36h、底物量为0.5g,糖化曲对秸秆的还原糖得率达到49.01%。(7)酒精发酵工艺研究。糖化液在发酵温度36℃、发酵时间96h、酵母菌量12%、起始pH值为5.5条件下发酵,酒精得率0.1972g.g-1红麻秸秆,是理论产值的74.21%。更多还原

【Abstract】 Kenaf is bast fiber and annual dioecious plant,that has great production,its stem are conposed of cellulose, hemicellulose,lignin and pectin that can convert to ethonal.Kenaf are used as material,we screened four fungus F2,H8,P11,L3 from cruptive corn stalks and soil which can respectively produce cellulose,hemicellulase, pectase,ligninase and researched the best conditions in which they can produce relevant enzyme with kenaf powder and wheat bran for the main raw material were studied;eventually techniques of saccharification and fermentation are studied.The results as follows: (1) By using cellulose congo-red culture medium and filter paper medium,we got the preliminary screening results that 18 strains can produce cellulase;by using the rate of cellulose -enzyme reaction,we got the final screening results.By such repeating screening,we got a strain of fungi which had a good ability to degrade cellulose from the samples we got from cruptive corn stalks and soil.The optimum conditions for enzyme production is 30℃, pH=6,the sixth day for 198.06U/g. (2) Screening fungus which can degrade hemicellulase and researching the best conditions:firstly we isolated fungus from samples we got from cruptive corn stalks and soil.13 strains are got by primary screening,we got a strain of fungi which had a good ability to degrade hemicellulose by repeating screening,the optimum conditions for enzyme production is 30℃,pH=5,the fifth day whose activity can reach maximum 1013.88U/g. (3) Screening fungus which can degrade pectin and researching the best conditions:by using congo-red culture medium we got 16 strains which can produce pectase;by the second screening we got a strain of fungi which had a good ability to degrade pectin from the samples we got from eruptive corn stalks and soil.The optimum conditions for enzyme production is 30℃,pH=5,the fifth day whose activity can reach maximum 239.39U/g. (4) Screening fungus which can degrade lignin and researching the best conditions:firstly we isolated fungus from samples we got from eruptive corn stalks and soil.8 strains are got by primary screening,by the second screening we got one shrain fungus which had a good ability to degrade lignin;the optimum conditions for enzyme production is 30℃,pH=5,the eighth day for laccase activity 294.81U/g. (5) By comparing kinds of pretreatment method,the method of 2%NaOH was the best method. (6) The best condition of saccharification was 55℃,pH=5.0,36h,pretreated material 0.5g,the reducing sugar was 49.01%. (7)The best condition of fermentation was 38℃,96h,fungus 12%,pH=5.0,the production of ethonal was 0.1972g. g-1.kenaf,an ethanol yield of 74.12%of theoretical maximum was achieved.更多还原