稀酸-碱湿法氧化预处理对玉米秸秆酶解性能影响

目的:为改善生物质纤维素酶解性能,提高玉米秸秆纤维素酶解葡萄糖收率,以实现玉米秸秆的综合利用。方法:采用稀酸-碱湿法氧化两步法预处理玉米秸秆,其中稀酸预处理步骤可回收半纤维素,碱湿法氧化预处理用于脱除木质素,考察碱湿法氧化预处理不同预处理条件对残渣纤维素酶解性能的影响,通过SEM、BET对预处理前后样品进行分析。结果:稀盐酸预处理可回收84.3%半纤维素;碱氧预处理(6%过氧化氢、18.3%氨水、130℃、30 min)后的残渣,当酶负载量为3 FPU/g,可回收65.7%葡萄糖。SEM结果表明预处理后秸秆表面孔隙及碎片增多,BET分析表明预处理后样品比表面积及孔隙率增大。结论:两步预处理通过分步脱除半纤维素、木质素,使秸秆基质结构破坏,纤维素酶的可及性增加,实现低酶用量下较高糖收率。     

稻草秸秆酶解条件优化

以高温预处理稻草秸秆为原料,分别进行纤维素酶、木聚糖酶单因子和正交试验,探索秸秆适宜工艺条件。结果表明:在1∶8的酶解固液比条件下,添加纤维素酶15 FPU/g底物和木聚糖酶200 IU/g底物,于50℃温度下酶解48 h,将获得82.13%的还原糖得率。说明以纤维素酶及木聚糖酶处理稻草秸秆是可行方法之一。     

液氨预处理(LAT)促进玉米秸秆的高效酶解糖化

采用液氨预处理(LAT)法预处理玉米秸秆,通过对预处理条件优化和高效液相色谱(HPLC)法测定酶解液中的单糖含量,考察了温度、含水率、预处理时间等因素对酶解糖化效果的影响,并对整个过程进行了质量平衡分析.实验结果表明,LAT法预处理能显著提高玉米秸秆的酶解转化率;在优化条件下,纤维素酶添加量为15 FPU/(g葡聚糖)时,葡聚糖和木聚糖的72 h酶解率分别为91.8％和82.1％,可达理论转化率的88％,单糖产量是未经预处理原料的2.1倍,每千克干基秸秆原料可生产单糖524.3g.通过与其他预处理方法的对比分析,LAT法预处理后的酶解转化率和单糖产量高于酸、碱、热水、汽爆等预处理方法.     

不同预处理对禾本绿竹生产纤维素乙醇糖化效果的比较研究

竹材是一种年产量很高的生物质材料,就绿竹而言每公顷有12 000 kg的生物质产量,其纤维含量较高,纤维性能较好,非常适合进行纤维素乙醇的转化生产。以绿竹为生物质原料,进行了热水处理、氨爆处理以及蒸爆处理,然后添加纤维素酶和淀粉酶进行酶解,并利用高效液相色谱(HPLC)测定了生物质中的单糖含量。研究结果表明,热水处理在保温时间10 min时,生物质葡萄糖转化率为28.45%,木糖转化率达到最高为45.55%,较未进行预处理分别提高了111.07%和224.23%。结果表明热水处理对绿竹是一种有效的预处理方式,其他两种预处理差别不大。研究成果对于生物质转化和利用具有十分有意义的。     

发酵农作物秸秆优良菌株木霉L-7发酵条件的优化

研究了木霉L-7利用稻草粉和玉米秸秆粉作为发酵基质进行的固态发酵;探讨了稻草粉和玉米秸秆粉的比例、碳源和氮源的种类、培养基含水量、培养基初始pH值、发酵温度、发酵时间及通气量对其产纤维素酶的影响。结果表明：最佳发酵培养基配方为稻草粉54.0g,玉米秸秆粉27.0g,麸皮19.0g,葡萄糖1.0g,硫酸铵1.0g,磷酸二氢钾0.1g,培养基含水量为1∶3;最优化培养条件为培养基初始pH值6.0,发酵温度30℃,发酵时间6天,通气量为60g/1000mL。在以上条件下,纤维素酶活达到最高。     

预处理对玉米秸秆发酵产氢的影响研究

以玉米秸秆为底物,以牛粪堆肥为菌种,研究了酸、碱预处理玉米秸秆对其发酵产氢能力的影响。结果表明,酸、碱预处理均能使样品中含糖量升高,并且硫酸预处理的效果高于氢氧化钠;硫酸的最佳处理浓度为0.3%、时间为6-8h。但其对设备的要求较高,对环境也有一定程度的污染。     

纤维素酒精蒸汽爆破预处理方法的研究

以玉米秸秆为原料进行纤维素乙醇生产,首先需要攻破的就是预处理技术[1],本文作者重点对汽爆预处理方法进行了大量试验研究,对比了间歇汽爆与连续汽爆的优劣之处,评估了两种工艺的预处理效率.     

里氏木霉ACCC30449纤维素酶特性的初步研究

通过对里氏木霉ACCC30449分泌的纤维素酶酶解条件比较,初步发现该菌株产生的纤维素酶的最适作用pH值为5,利用菌株产纤维素酶分解处理不同比例搭配的玉米秸杆和稻草,结果表明玉米秸杆：稻草= 3：1的时候,纤维素的分解速率最高。     

玉米基料复合杂豆营养粉配方优化

为开发一种方便消费者食用并符合当前营养健康需求的谷物精加工食品,该研究以改性后玉米粉为基料,添加适量的豆类,经超微粉碎、包装后获得一种新型复合杂豆营养粉。通过单因素试验分析了红豆粉、黑豆粉、绿豆粉的添加量对新型复合杂豆营养粉感官品质的影响,利用响应面试验优化复合杂豆营养粉的配方。结果表明：玉米基料复合杂豆营养粉的最佳配方：改性玉米超微粉20 g,红豆超微粉的添加量为玉米超微粉的15%(3 g)、黑豆超微粉的添加量为玉米超微粉的10%(2 g)、绿豆超微粉的添加量为玉米超微粉的20%(4 g)。该产品口感佳,溶解度和稳定性较好。     

基于微波辅助法从玉米秸秆中提取纤维素的研究

玉米秸秆中含有丰富纤维素,是天然的“纤维素库”。若将其提取出来加以利用,将会极大程度地提高秸秆的附加值,为生产生活带来便利。本实验采用微波辅助法处理玉米秸秆粉末,去除其中的半纤维素和木质素,提取其中的秸秆纤维素。利用傅里叶变换红外光谱、X射线衍射以及扫描电镜的方法从形貌、结构以及性能等方面对提取产物进行表征。探究NaOH溶液的质量分数、微波加热时间、微波加热功率、亚氯酸钠浓度以及料液比对提取率的影响,得到从玉米秸秆中提取秸秆纤维素的最佳实验条件为：NaOH溶液质量分数为12%,微波功率为595 W,微波加热时间为9 min, NaClO₂浓度为0.3 mol/L。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.