活菌制剂和复合酶制剂对青贮玉米秸秆化学组成及纤维微观结构的影响

Effects of Living Bacteria Preparation and Compound Enzymes Preparation on Chemical Composition and Microstructure of Fibers of Silage Corn Stover

本试验以酶制剂、酶-菌复合制剂对玉米秸秆进行生物发酵处理,分析其对玉米秸秆发酵品质、营养成分和纤维微观结构的影响,旨在探索通过打破纤维微观结构提高玉米秸秆利用率的作用机制。试验设置秸秆原料组(CS组)、青贮对照组(CK组)、复合酶制剂组(CPL组)、复合酶-单活菌组(CPLP组)、复合酶-双活菌组(CPLB组)。使用真空包装机抽空玉米秸秆青贮袋中的气体,室温发酵45 d后,分析各组青贮玉米秸秆的营养成分和发酵品质;采用苯酚硫酸法+4,4'二羧酸-2,2'-喹啉(BCA)法、傅里叶转换红外光谱(FTIR)、X-射线衍射和伊红美兰法分析各组玉米秸秆纤维微观结构。结果表明:1)与CK组相比,CPL组的p H、氨态氮/总氮(NH3-N/TN)和乳酸/乙酸显著降低(P<0.05),乳酸、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、纤维素、半纤维素含量无显著差异(P>0.05);CPLB组的乳酸含量显著增加(P<0.05);CPLP和CPLB组的p H、NH3-N/TN、乳酸/乙酸以及NDF、ADF、纤维素、半纤维素含量均显著降低(P<0.05)。2)与CK组相比,CPL组的三级结构结晶度显著升高(P<0.05),一级结构聚合度和四级结构比表面积无显著差异(P>0.05),二级结构氢键作用力无明显变化;CPLP和CPLB组的一级结构聚合度显著降低(P<0.05),四级结构比表面积显著增高(P<0.05),二级结构氢键作用力减弱,三级结构结晶度无显著差异(P>0.05)。综上,复合酶-单活菌和复合酶-双活菌显著改善了玉米秸秆的化学组成,通过降低玉米秸秆纤维素的一级结构聚合度和三级结构中纤维素非结晶区,减弱二级结构分子间氢键作用力,增加四级结构比表面积,有效地破解了玉米秸秆细胞壁的微观结构,从而提高了秸秆的利用率。

This study was conducted to investigate the effects of corn stover treated by enzyme preparation and enzyme-bacteria compound preparation on fermentation quality,nutrition composition and microstructure of fibers,and aimed to explore its mechanism of improving corn stover utilization by breaking the cellulose microstructure.Five groups were designed in the present study:corn stover group(CS group),silage control group(CK group),corn stover treated by compound enzyme group(CPL group),corn stover treated by compound enzyme and single living bacteria group(CPLP group),and corn stover treated by double living bacteria group(CPLB group).Samples were prepared by vacuum packager in polyethylene bags,after storing at room temperature for 45 d,the chemical composition and fermentation quality of silage corn stover were measured.Additionally,the microstructure of fibers was analyzed by phenol-sulfuric acid+4,4′-dicarboxy-2,2′-biquinoline disodium(BCA)methods,Fourier transform infared spectroscopy(FTIR),X-ray diffraction and iran methylene method.The results showed as follows:1)compared with the CK group,the pH,ratio of ammonia nitrogen to total nitrogen(NH 3-N/TN)and ratio of acetic acid to lactic acid in the CPL group were significantly decreased(P<0.05),the contents of lactic acid,neutral detergent fiber(NDF),acid washing fiber(ADF),cellulose and hemicellulose in the CPL group had no significant difference(P>0.05);the content of lactic acid in the CPLB group was significantly increased(P<0.05);the pH,NH 3-N/TN,ratio of acetic acid to lactic acid and contents of NDF,ADF,cellulose and hemicellulose in CPLP and CPLB groups were significantly decreased(P<0.05).2)Compared with the CK group,the crystallinity of tertiary structure in the CPL group was significantly increased(P<0.05),the degree of polymerization of primary structure and specific surface area of quaternary structure had no significant difference(P>0.05),the intermolecular hydrogen bonding force of secondary structure did not change;the degree of polymerization of primary structure in PLP and CPLB groups were significantly decreased(P<0.05),the specific surface area of quaternary structure were significantly increased(P<0.05);the intermolecular hydrogen bonding force of secondary structure was weakened,the crystallinity of tertiary structure had no significant difference(P<0.05).In conclusion,the compound enzyme-single living bacteria and compound enzyme-double living bacteria can significantly improve the chemical composition of corn stover,it can effectively crack down the microstructure of the cell wall of corn stovers by reducing the degree of polymerization of primary structure and the amorphous area of tertiary structure,weakening the intermolecular hydrogen bonding force of secondary structure and increasing the specific surface area of quaternary structure from cellulose of corn stover,and enhancing the utilization rate of straw.