【作者】 韩善明；

【导师】 房桂干；

【作者基本信息】 中国林业科学研究院 ， 林产化学加工工程， 2008， 博士

【摘要】 杨树是我国速生工业用材林的重要树种,在长江流域及以北地区广泛种植。以杨木为主要原料的大型制浆生产线先后建成投产,主要采用的制浆技术包括BCTMP、APMP和P-RC APMP等。由于P-RC APMP制浆技术具有工艺流程紧凑,原料适性广,有效协调了松厚度与强度之间的关系等优点,近年来在我国速生阔叶材林浆纸一体化工程建设中,选用的厂家较多。白腐菌能够降解植物纤维中的木质素,人们试图将白腐菌此种特性引入制浆造纸过程,多年来,进行了较多的探索和努力,取得了令人兴奋的成果,但目前还未见产业化应用的报道,实验室研究工作仍然处于方兴未艾的局面,着力解决产业化技术开发的前期瓶颈问题。本论文选用4株高效白腐菌株(Pycnoporus cinnabarinus,Pycnoporus sanguimeus,Tranetes versicolor和Phanerochaete chryscoporium)对杨木木片进行预处理,将白腐菌处理和P-RC APMP制浆相结合,试图在降低化学品消耗,降低磨浆能耗,提高纸浆的质量,改善废水污染特征等方面有所进步。同时在此基础上,揭示白腐菌用于预处理杨木而改善制浆性能的机理,为生物化机浆的技术开发提供理论依据。以降解木质素效率为考核目标,优化了所选用的4株白腐菌预处理杨木木片的适宜条件,结果表明,适宜温度为29oC,适宜的培养基pH值为3.5。同时还发现,在外加碳源充足时白腐菌几乎不降解纤维素和半纤维素,而是选择性的降解木质素。有效改善了这4株白腐菌对木质素降解的选择性。在同样的预处理条件下,比较4株白腐菌的作用效果,旨在筛选合适的菌株。研究表明,Ph.c生长速度快,环境适应性强,木质素的降解效率高且具有良好的选择性,为缩短处理时间提供了条件;T.v损失纤维素和半纤维素较少而降解的木质素较多,降解木质素的选择性比Py.s和Py.c高。木质素降解的选择性Ph.c>T.v>Py.s>Py.c。利用电子显微镜观察了白腐菌在杨木木片上生长和对杨木降解的过程。在白腐菌处理过程中,白腐菌在木片表面迅速生长,覆盖木片表面。通过导管进入木片内部,并通过纹孔进入周围的细胞。利用SEM/EDXA测定了处理过程中杨木各部分木质素浓度的变化。开始两周胞间层和细胞角木质素浓度下降较快,细胞壁S2层由于纤维素的阻碍,木质素浓度下降较慢。随处理时间的延长,胞间层木质素浓度下降速度基本保持不变,细胞角木质素浓度下降逐渐减慢,而细胞壁S2层木质素由于纤维素和半纤维素的降解量的增加而降解逐渐加快。培养基的加入不但可以保护纤维素和半纤维素,而且间接保护了细胞壁木质素,这对于生物机械法制浆有重要意义。为了阐明白腐菌降解杨木木质素的机理,利用气相色谱/质谱、核磁共振等手段测定了白腐菌处理杨木的产物和处理后木质素中各基团含量。白腐菌降解木质素主要通过Cα-Cβ氧化断裂,其次为β-O-4键断裂。同时白腐菌还对木质素进行脱甲氧基作用。为了考核白腐菌预处理对杨木木片在制浆性能方面的作用,将白腐菌处理后杨木木片和对照样采用两个不同用药量工艺进行P-RC APMP制浆,结果表明:白腐菌处理可以大量降低磨浆能耗,磨浆至350CSF时,工艺1条件下,Ph.c处理降低能耗30%以上,T.v处理降低11%,工艺2条件下,Ph.c处理和T.v处理都降低能耗14.37%。白腐菌预处理后制P-RC APMP浆可以提高浆的强度,在低用药量下,白腐菌处理对撕裂强度改善作用更明显,在高用药量下,白腐菌处理对耐破强度改善作用更明显。白腐菌处理改善了木片的可漂性。由于白腐菌处理产生的有机物在后续磨浆漂白过程中消耗掉部分药品,在低用药量下,白腐菌处理后制P-RC APMP浆白度比对照低,但在高用药量下相差不大,T.v处理样P-RC APMP浆的白度比对照样更高。由于白腐菌处理使木片中含有大量的菌丝、有机酸和酶等,而且白腐菌处理降解了部分木质素,也使药液更容易渗透,有较多的木质素溶出进入废水,使废水的污染负荷比对照样高得多,同时可生化性也高。白腐菌预处理降解了部分木质素,白腐菌产生的酶和菌丝等也在制浆过程中进入废水,白腐菌预处理P-RC APMP制浆废水污染负荷比对照样高,但可生化性好,而且废水中物质容易被微生物降解,所以废水处理去除率比对照样高,出水水质比对照样好。更多还原

【Abstract】 Poplar is an important fast-grow specie for industry in China, which was planted widely on Changjiang river and north area. Several high yield pulp lines had been built in recent years, which mostly use BCTMP, APMP and P-RC APMP technology, poplar was major resourse. P-RC APMP technology has the benefit of sequnce flow compact, material adaptability wide and has both good bulk and good strength quality, has been used in many fast-grow hard wood pulping mill in resent years. White rot fungi could delignification of fibre, many research has been carried on to introduce it into pulp industry and much progress has been done, but still can’t industrialization. Now, there are many research trying to resolve the problems of industrialization. In this paper, 4 white rot fungi (Pycnoporus cinnabarinus, Pycnoporus sanguimeus, Tranetes versicolor and Phanerochaete chryscoporium) were used to treating poplar chips, then the chips were milled by P-RC APMP sequence. Combining the benefit of bio-treatment and P-RC APMP, we try to make some progress on reduceing the energy consumption or chmical consumption of pulping, enhancing the quality of pulp and reforming effluent treatment. The mechanism and the optimal codition of white rot fungi treating poplar chips were also studied to supply a theory foundation on bio-chmimechnical pulping technology.Use delignification of poplar as the target, the culture conditions of white rog fungi treating poplar were optimized, the result showed that: the best culture condition for white rot fungi growing and treating poplar chips was temperature 29 oC and pH 3.5. The 4 white rot fungi don’t decompose cellulose and hemecellulose until the carbon source was used out, it showed good selectivity of delignification. Ph.c has good adaptability, grows much faster and more efficiently of delignification than others, so it need less time to treating chips. The selectivity of delignification: Ph.c>T.v>Py.s>Py.c.SEM was utilized to observe the process of white rot fungi growing on poplar chips. White rot fungi grows fast, and cover chips in a few days, the mycelium went into chips through vessels, and then went into other cells through pits. Lignin thichness of poplar chip treated by white rot fungi for different time was tested by SEM/EDXA. At the beginning of bio-treatment, the thichness of lignin at cell middle lamella and cell corner reduced rapidly. Because of the cumber of cellulose and hemicellulose, the thichness of lignin at cell wall s2 reduced much slower. When bio-treatment keeping on, cellulose and hemicellulose degraded much,the thichness of lignin at cell wall s2 reduced faster and faster, and the thichness of lignin at cell corner reduced slowly down, the thichness of lignin at cell middle lamella kept the speed reducing. The culture medium added not only protected cellulose and hemecelloluse, but also protected lignin in cell wall indirectly. It was very important to bio-chemimechanical pulping. White rot fungi decompose lignin mostly depends on cutting Cα-Cβandβ-O-4 bond.After bio-treatment, poplar chips were pulped by two P-RC APMP sequnces. The result showed that: white rot fungi treatment could save much energy consumption of milling, when freeness of pulp was 350CSF, Ph.c could save more than 30% of energy in sequence 1 and T.v could save 11%, both Ph.c and T.v could save 14.37% in sequence 2.White rot fungi pretreatment could enhance the strength of pulp. When the dosage of chemical was low, the enhancement of tear strength was much evident; when the dosage of chemical was high, the enhancement of burst strength was much evident. Because the organic compounds white rot fungi made cost much chemical, when the dosage of chemical was low, pulp with bio-treatment had lower brightness than control, but when the dosage of chemical was high, the pulp with bio-treatment had higher brightness than control. That means white rot fungi could improve the bleachability of chips.White rot fungi treatment made much mycelium, organism acid and enzymes, much of them went into the effluent. White rot fungi decomposed some lignin and made chemicals easier to infiltrate into chips, which made more lignin dessloved into effluent. So, the effluent of white rot fungi treated sample had higher load than control.White rot fungi pretreatment degraded some lignin, and it made enzymes and hypha. Much of them entered the effluent of pulping. So the pollution charge of white rot fungi pre-treated P-RC APMP effluent was higher than control, but it was much easyer to be treated, more pollutant could be moved off.更多还原