不同酶及组合处理对青贮水稻秸秆微观结构的影响

本试验以水稻秸秆为研究对象,采用高效降解纤维素酶进行青贮发酵处理,分析其对水稻秸秆微观结构的影响,旨在实现农作物秸秆的高效降解,提高其营养价值。设青贮对照(S组)、复合酶制剂处理(C组)、果胶酶+漆酶处理(PL组)、复合酶制剂+果胶酶+漆酶处理(CPL组)和原料(M组),各组采用袋装真空青贮。室温贮藏45 d后取样,采用实验室检测方法、苯酚硫酸法、4,4'二羧酸-2,2'-喹啉(BCA)法、近红外光谱(FTIR)、X-射线衍射和伊红美兰法分析不同酶或酶组合处理的水稻秸秆青贮饲料的营养成分含量、发酵品质及微观结构变化。结果表明:1)与S组相比,PL组、C组及CPL组的乳酸(LA)含量显著增加(P0.05),p H、氨态氮/总氮及乙酸、纤维素含量均显著降低(P0.05);CPL组、C组的粗蛋白质含量显著降低(P0.05)。2)与S组相比,PL组青贮水稻秸秆的聚合度显著降低(P0.05),降低幅度达30.26%,分子间氢键结合力减弱,结晶度与比表面积无显著变化(P0.05);C组青贮水稻秸秆聚合度显著降低(P0.05),降低幅度达27.11%,分子间氢键结合力减弱,结晶度与比表面积无显著变化(P0.05);CPL组青贮水稻秸秆的聚合度显著降低(P0.05),降低幅度达56.32%,分子间氢键结合力减弱,有降低结晶度和增加比表面积的趋势(P0.05)。综上,CPL组降解纤维组分的效果最理想,能有效地破解细胞壁中木质素-纤维素-半纤维素复合结构,将纤维素降解为可利用的糖,提高水稻秸秆青贮饲料的营养含量,降低聚合度及结晶度,增大比表面积,从而提高秸秆的可消化性及利用率。

Effect of Different Enzymes and Their Combinations on Microstructure of Rice Straw Silage

In order to achieve the high-efficiency degradation of crop straw and improve its nutritional value, high efficient degrading enzymes for silage fermentation were used to investigate their effects of microstructure of rice straw silage. Silage control ( S group) , compound enzyme preparation treated ( C group) , pectinase+laccase treated ( PL group) , compound enzyme preparation+pectinase+laccase treated ( CPL group) and raw material ( M group) were used and samples were packaged by vacuum packager in polyethylene bags. After storing at room temperature for 45 d, changes of the silage quality and nutrients content were analyzed using la-boratory testing methods, and changes of microstructure were analyzed using phehol-suffufic acid colorimetry, bicinchoninic acid disodium salt ( BCA) method, fourier transform infared spectroscopy ( FTIR) , X-ray dif-fraction analysis and eosin-methylene blue method. The results showed as follows: 1 ) compared with the S group, the lactic acid ( LA) content in PL, C and CPL groups was significantly increased ( P<0.05) , the pH, ratio of ammonia nitrogen to total nitrogen and content of acetic acid and cellulose were significantly decreased (P<0.05); the crude protein (CP) content in C and CPL groups was significantly decreased (P<0.05). 2) Compared with the S group, the polymerization degree of rice straw silage in PL group was significantly de-creased (P<0.05), which was lowered by 30.26%, the intermolecular hydrogen bond binding force was fa-ded, and specific surface area and crystallinity did not change (P>0.05); the polymerization degree of rice straw silage in C group was significantly decreased (P<0.05), which was lowered by 27.11%, the intermo-lecular hydrogen bond binding force was faded, and specific surface area and crystallinity did not change ( P>0.05); the polymerization degree of rice straw silage in CPL group was significantly decreased (P<0.05), which was lowered by 56.32%, the intermolecular hydrogen bond binding force was faded, and specific sur-face area and crystallinity trend increased ( P>0.05) . In conclusion, CPL group has the best effect, it can ef-fectively break the lignin-cellulose-hemicellulose composite structure and cellulose degraded into available sug-ar, improve the nutrient content of rice straw silage fodder, reduce the degree of polymerization and the crys-tallinity, increase the specific surface area, so as to improve the digestibility and utilization of the straw.