【作者】 王芳芳；

【导师】 黄峰；

【作者基本信息】 山东轻工业学院 ， 制浆造纸工程， 2011， 硕士

【摘要】 玉米秸皮含有37.62%的硝酸乙醇纤维素,重均纤维长度为0.987,它比全玉米秸秆更适合于做造纸原料。同时考虑到目前机械法制浆高能耗、化学制浆引起环境污染的问题。本论文采用新的木质纤维素原料——玉米秸皮作为造纸原料进行生物机械法制浆的研究。通过Bavendamm-PDA平板从济南长清玉米种植地筛选出四株产生变色反应的菌株。从山东大学微生物技术国家重点实验室获得的五株菌中Phanerochaete chrysosporium-25和Phanerochaete chrysosporium-14的Bavendamm-PDA平板呈阴性,Trametes hirsuta lg-9,Trametes versicolor,Irpex lacteus均呈阳性。这9种菌株的玉米秸皮降解实验结果显示对玉米秸皮选择性降解的顺序为:Trametes hirsuta lg-9 > Sd > P.C.-14 > P.C.-25 > Trametes versicolor > Sc。将筛选到的对玉米秸皮选择性降解最强的菌株Trametes hirsuta lg-9用于玉米秸皮生物机械法制浆的研究。通过不同菌龄、不同培养方式得到的接种物接种玉米秸皮在无外通空气和连续通空气两种条件下预处理玉米秸皮45d制机械浆,得到的结果显示无外通空气方式培养,低菌龄的接种物处理得到的纸浆强度优于高菌龄;同菌龄的培养物,固态静置培养接种物处理样强度性能优于液态震荡培养接种物。连续通空气培养时,由于打浆度上的差异,有待研究。用固态静置培养物接种,无外通空气方式引起的重量损失小于外通空气,且强度性能也优于后者。用液态震荡培养物接种,则结果相反。Trametes hirsuta lg-9预处理引起了玉米秸皮机械浆白度和光散射系数的降低和光吸收系数的增加。且Trametes hirsuta lg-9预处理后的玉米秸皮在所研究的两段磨浆条件下,引起的磨浆能耗降低幅度在70-85%之间。另外研究发现Trametes hirsuta lg-9玉米秸皮生物机械浆的强度性能与打浆过程中引起的细小增量与保水值增量的比值有较好的线性正相关关系。通过预处理时间对Trametes hirsuta lg-9玉米秸皮制生物机械浆影响的研究发现,Trametes hirsuta lg-9预处理玉米秸皮过程中产木聚糖酶、纤维素酶和漆酶,产酶量顺序为木聚糖酶>纤维素酶>漆酶。产酶速率表现为初期增加较快,中期减缓,后期降低的趋势。且Trametes hirsuta lg-9预处理玉米秸皮引起了发酵体系pH的变化。磨浆段能耗的测定结果显示磨浆能耗随着处理时间不断降低,且在α=0.1时,磨浆能耗与Trametes hirsuta lg-9预处理过程中的产酶量无相关性,而与Trametes hirsuta lg-9预处理后的玉米秸皮红外光谱3414cm~-1和1653cm~-1的相对吸收强度具有线性相关性。造成Trametes hirsuta lg-9玉米秸皮机械浆的强度随着处理时间降低的原因是纤维素酶不断积累引起纤维素解聚,引起α-纤维素含量的降低。Trametes hirsuta lg-9预处理秸皮增加了脂肪族羰基和与苯环共轭的羰基含量,因此引起了Trametes hirsuta lg-9预处理玉米秸皮机械浆的光吸收系数的增加,从而降低了纸浆的白度。Trametes hirsuta lg-9预处理玉米秸皮过程中对愈疮木基的降解多于紫丁香基的降解,且预处理初期对纤维素的结晶区降解多于无定形区,而后期以对无定形区的降解为主。Trametes hirsuta lg-9预处理玉米秸皮的显微观察显示Trametes hirsuta lg-9对玉米秸皮的侵入从表皮细胞开始逐渐深入到薄组织和维管束部分。更多还原

【Abstract】 Corn stalk barks contain 37.62% nitric acid-ethanol cellulose and their weight-average fiber length is 0.987, so they are more suitable for using as paper-making materials than the whole corn stalk. Besides, to avoid the high electric consumption of mechanical pulping and environmental pollution caused by chemical pulping in current pulping and paper-making industry, the thesis adapted the new lignocellulosic materials—corn stalk barks as raw material to carry out the research on biomechanical pulping.Four stains that produced colored reaction were isolated from planted ground of corn at ChangQing district in Jinan by Bavendamm-PDA plate. Among the five stains obtained from the state key laboratory of microbial technology in Shandong university, Bavendamm-PDA plate of Phanerochaete chrysosporium-25 and Phanerochaete chrysosporium-14 was negative, that of Trametes hirsuta lg-9,Trametes versicolor,Irpex lacteus was positive. The experiment of degradation of corn stalk barks by the nine strains showed that the sequence of selective degradation on corn stalk barks was: Trametes hirsuta lg-9 > Sd > P.C.-14 > P.C.-25 > Trametes versicolor>Sc.The strongest selective degrading strains on corn stalk barks isolated—Trametes hirsuta lg-9 was applied to corn stalk barks biomechanical pulping. Mechanical pulpling of corn stalk barks was performed after pretreated in no-exogenous air or aeration by different age inoculums gained by different cultivated method. The results indicated that in no-exogenous air, the strength of pulp made from corn stalk barks treated by young age inoculums was superior to samples treated by old age inoculums; with regard to the same age inoculums, the strength of sample treated by solid static cultivated inoculums excelled those treated by liquid shaking cultivated inoculums. In continuous aeration, further research was required due to the discrimination of the beating degree. When corn stalk barks were inoculated by solid static inoculums, the weight loss in no-exogenous air was less than that in continuous aeration and its strength property was also better than the latter. While corn stalk barks were treated by liquid shaking cultivated inoculums, the outcome was opposite. Pretreatment by Trametes hirsuta lg-9 caused the decrease of brightness and light scattering coefficient of corn stalk barks mechanical pulp and the increase of light absorption coefficient. And the energy consumption of corn stalk barks after treated by Trametes hirsuta lg-9 in the two-stage refining condition studied reduced from 70% to 85%. In addition, the research discovered the positive linear correlation between the strength property of biomechanical pulp of corn stalk barks pretreated by Trametes hirsuta lg-9 and the ratio of increment of fine caused by beating to increment of water retention value was significant.The research of effect of pretreatment time on biomechanical pulping of corn stalk barks treated by Trametes hirsuta lg-9 indicated during the course of pretreatment of corn stalk barks, Trametes hirsuta lg-9 produced xylanase, cellulase, and laccase and the sequence of yield of enzyme was: xylanase>cellulase>laccase. The ratio of producing enzyme increased quickly in early period, slowed down in middle period, and decreased in last stage. And the pretreatment by Trametes hirsuta lg-9 caused change of pH of the fermentation system. The result of energy consumption estimation during refining indicated the electric consumption constantly reduced with time, and ifα=0.1 was chosen as th significant level, there was no correlation between the energy consumption and yield of enzyme produced in the course of pretreatment, but there was linear correlation between the energy consumption and the relative absorption intensity of 3414cm-1 and 1653cm-1 in infrared spectrum of corn stalk barks pretreated by Trametes hirsuta lg-9. The reason why led to the reduction of strength of corn stalk barks biomechanical pulp by Trametes hirsuta lg-9 as pretreatment time was that the continuous accumulation of cellulase brought about the depolymerization of cellulose, and eventually caused the decrease ofα-cellulose content. The pretreatment by Trametes hirsuta lg-9 raised the number of aliphatic carbonyl group and carbonyl group conjugated to benzene ring, so the light absorption coefficient of corn stalk barks biomechanical pulp by Trametes hirsuta lg-9 increased, and finally pulp brightness decreased. During the pretreatment of corn stalk barks by Trametes hirsuta lg-9, the degradation of the guaiacyl unit was more than that of the syringyl unit, and in early period the degradation of crystalline region predominated, while in latter period the degradation of amorphous region was principal. Microscopic observation of corn stalk barks pretreated by Trametes hirsuta lg-9 revealed invasion of hypha of Trametes hirsuta lg-9 began with epidermal cell and gradually penetrated into parenchymas and vascular bundles.更多还原