Production and application of bacterial cellulose for a filler of composite materials.

研究了将处于单晶状态的细菌纤维素（BC）用作复合材料的填料。BC膜经硬脂酸处理后具有疏水性，并与环氧树脂复合。不含填料的对照和含有13%未改性的BC膜并以取代度2对其进行改性的复合材料的拉伸强度的比率在通过比重校正的值中分别为1.0、2.0和3.5。采用甲基丙烯酸甲酯（MMA）等对BC膜和经均质器微纤化的BC纤维（MFBC）进行接枝共聚改性，并与环氧树脂等复合，所得复合材料的拉伸强度比未改性的MFBC提高50%。将通过纤维素材料的酶糖化获得的溶液用作培养基。与原设想相比，用标准HS培养基加纯葡萄糖酶发酵，BC产量提高30 ~ 70%。结果表明，这是由于纤维素酶在热杀菌过程中失去了糖化活性所致。在HS培养基中添加改性纤维素酶，可使细菌纤维素产量提高近2倍。纤维素酶分为纯酶、内切氧化酶、外切氧化酶和β氧化酶。修饰的β-氧化酶对增加的贡献最大。这表明修饰后的酶通过与葡萄糖形成复合物为葡萄糖键合提供了理想的条件。另一个原因是葡萄糖中存在一定比例的甘露糖和半乳糖。从醋酸杆菌质粒中获得的PFF 6（4.8kB）和从大肠杆菌质粒中获得的PUC 18（2.7kB）载体适合于外源DNA的插入，转化效率均在10^4/1 μ g以上。

It was studied to use bacterial cellulose (BC) in the state of single crystallite as a filler for a composite material. BC membrane was stearlated to be given hydrophobicity and composed with epoxy resin. The ratios of tensile strength of the control without the filler and the composite matirials contained 13% of unmodified BC membrane and modified it in the degree of substitution of 2 were 1.0, 2.0, and 3.5 in the value corrected by specific gravity, respectively. Also, BC membrane and BC fiber microfibrilized with a homogenizer (MFBC) were modified by graft copolymerization with methylmetacrylate (MMA) and etc. and composed with epoxy resin and etc. Tensile strength of composite material of MFBC graft polymerized with MMA and epoxy resin increased 50% compared with that used unmodified MFBC.To decrease production cost of BC, solution obtained by enzymatic saccharification of cellulosic materials was used as cultivation medium. In contrast to presuppose amount of producted BC increased 30 to 70% compared with that used standard HS medium with pure glucase. It was cleared that the reason was brougth from the cellulase lost saccharification activity during heat sterilization. Addition of the modified cellulase into the HS medium brougth an increasing of almost 2 times in the yield of BC. Cellulase was seperated pure enzyme, endo-, exo-, and beta oxydase. the modified beta oxydase was most contributed to the increasing. It suggested that the modified enzayme provided a desirable situation for bonding of glucoses by forming a complex with them. The another reason was on the coexistence of mannose and galactose in some ratio with glucose.Shuttle vectrs for cellulose-producing Bacterium Acetobacter were diviloed. The vectors formed PFF6(4.8kB) from plasmid of the acetobactor and it of PUC18(2.7kB) from it of a colon bacillus was fit for insertion of pieces of foreign DNA, and had a high transformation efficiency of the level over 10^4/1ug.