外源多糖降解酶对纯底物发酵动力学及消失率影响

采用活体外产气量法测定外源添加的纤维素酶、木聚糖酶和β-葡聚糖酶对绵羊瘤胃发酵动力学及消失率的影响。以木聚糖和微晶纤维素为底物,选用木聚糖?微晶纤维素和木聚糖与微晶纤维素的等量混合物0.2g,酶添加水平分别为:纤维素酶为0,5000,10000和15000U/mL;木聚糖酶为0,360,3600和36000U/mL;β-葡聚糖酶为0,320,3200,和32000U/mL,每个组设3个重复,来测定3种酶对瘤胃降解微晶纤维素和木聚糖及二者混合物的产气速率、延滞期和最大产气量的影响。试验结果显示,利用体外产气量法测定外源多糖降解酶对以纯微晶纤维素和木聚糖为底物96h的消失率影响不显著(P>0.05),对底物的发酵动力学的影响,不同处理、不同酶及底物之间也不相同,木聚糖酶试验中,2种底物在消失率方面有相互促进作用。

Effects of supplementation of exogenous polysaccharide degrading enzymes on the degradation rate and kinetic gas production of pure substrates

The aim of this experiment was to investigate the effect of supplementation of exogenous polysaccharide degrading enzymes(cellulase, xylanase, and β-glucanase)on the kinetic gas production and degradation of pure microcrystalline cellulose, xylan and its mixture (1∶1) by using the in vitro gas production techniques. Supplemental levels of cellulose were 0, 5 000, 10 000 and 15 000 U/mL, xylanase were 0, 360, 3 600 and 36 000 U/mL, and glucanase were 0, 320, 3 200 and 32 000 U/mL. The weight of each substrate in the syringe was 0.2 g with three replications of each treatment. The total volume of gas production at each time point were recorded and the final degradation rate were determined when the fermentations were stop. The kinetic parameters of gas production were analyzed with the NLIN model of SAS program. The results showed that there were no significant differences in degradation rates between control and treatment groups, however, the gas production rates in treatment groups were significantly increased while the lag times were shortened by supplementation of exogenous polysaccharide enzymes compared with their corresponding controls.