Investigation of the nutritional and functional roles of a combinational use of xylanase and β-glucanase on intestinal health and growth of nursery pigs

Background Xylanase andβ-glucanase combination(XG)hydrolyzes soluble non-starch polysaccharides that are anti-nutritional compounds.This study aimed to evaluate the effects of increasing levels of XG on intestinal health and growth performance of nursery pigs.Methods Forty pigs(6.5±0.4 kg)were assigned to 5 dietary treatments and fed for 35 d in 3 phases(11,9,and 15 d,respectively).Basal diets mainly included corn,soybean meal,and corn distiller's dried grains with solubles,contained phytase(750 FTU/kg),and were supplemented with 5 levels of XG at(1)0,(2)280 TXU/kg xylanase and 125 TGU/kgβ-glucanase,(3)560 and 250,(4)840 and 375,or(5)1,120 and 500,respectively.Growth performance was measured.On d 35,all pigs were euthanized and jejunal mucosa,jejunal digesta,jejunal tissues,and ileal digesta were collected to determine the effects of increasing XG levels and XG intake on intestinal health.Results Increasing XG intake tended to quadratically decrease(P=0.059)viscosity of jejunal digesta(min:1.74 m Pa·s at 751/335(TXU/TGU)/kg).Increasing levels of XG quadratically decreased(P<0.05)Prevotellaceae(min:0.6%at 630/281(TXU/TGU)/kg)in the jejunal mucosa.Increasing XG intake quadratically increased(P<0.05)Lactobacillaceae(max:40.3%at 608/271(TXU/TGU)/kg)in the jejunal mucosa.Increasing XG intake quadratically decreased(P<0.05)Helicobacteraceae(min:1.6%at 560/250(TXU/TGU)/kg)in the jejunal mucosa.Increasing levels of XG tended to linearly decrease(P=0.073)jejunal Ig G and tended to quadratically increase(P=0.085)jejunal villus height to crypt depth ratio(max:2.62 at 560/250(TXU/TGU)/kg).Increasing XG intake tended to linearly increase the apparent ileal digestibility of dry matter(P=0.087)and ether extract(P=0.065).Increasing XG intake linearly increased(P<0.05)average daily gain.Conclusions A combinational use of xylanase andβ-glucanase would hydrolyze the non-starch polysaccharides fractions,positively modulating the jejunal mucosa-associated microbiota.Increased intake of these enzyme combination possibly reduced digesta viscosity and humoral immune response in the jejunum resulting in improved intestinal structure,and ileal digestibility of nutrients,and finally improving growth of nursery pigs.The beneficial effects were maximized at a combination of 550 to 800 TXU/kg xylanase and 250 to 360 TGU/kgβ-glucanase.

Characterization of Exo 1, 4-<i>β</i>glucanase produced from <i>Tricoderma Viridi</i>MBL through solid-state bio-processing of orange peel waste

Agro-industrial residues are primarily composed of complex polysaccharides that strengthen the microbial growth for the production of industrially important enzymes like cellulases. In the present study we aimed to characterize the Exo 1, 4-β glucanase that was indigenously produced from Trichoderma viride MBL. T. viride MBL was cultured in the Solid-State medium of orange peel (50% w/w moisture) under optimized fermentation conditions and maximum activity of 412 ± 12 U/mL was recorded after 4th day of incubation at pH 5.5 and 30℃. Exo 1, 4-β glucanase was 4.17-fold purified with specific activity of 642 U/mg in comparison to the crude extract. To confirm its purity and molecular weight, sodium dodecyl sulphate poly acrylamide gel electrophoresis (SDS- PAGE) was performed. The enzyme was shown to have a molecular weight of 60 kDa with an optimum pH and temperature of 5 and 50℃, respectively. Lineweaver-Burk reciprocal plot revealed that the kinetic constants Km and Vmax of purified Exo 1, 4-β glucanase were 76 μM and 240 U/mL.

Purification and some properties of a β-glucanase from a strain, Trichoderma reesei GXC

glucanase was purified from a solid\|state culture of \%Trichoderma reesei \%on wheat bran in three steps which comprised ammonium sulfate precipitation, Sephadex G\|100 chromatography, and DEAE\|Sephadex A\|50 chromatography. The molecular mass was determined to be 35.21 kilodaltons by sodium dodecyl sulfate\|12.5% polyacrylamide gel electrophoresis. The \%β\%\|glucanase at low pHs was more stable than that at high pHs, and optimum pH was 5.0. The optimum temperature was 60 ℃, and \%β\%\|glucanase was relatively stable at below 40 ℃ for 60 min. The \%K\%\-m of the enzyme on \%β\%\|glucan was 10.86 mg/ml, and the \%V\%\-\{max\} on \%β\%\|glucan was 14286 μmol of glucose equivalents per mg of the pure enzyme per min. The \%β\%\|glucanase activity was significantly inhibited by Fe\+\{3+\} ions, and was reduced in the presence of Cu\+\{2+\} ions, Mn\+\{2+\} ions and Mg\+\{2+\} ions at 5 mmol/L and 10 mmol/L, respectively. The \%β\%\|glucanase activity was stimulated by Co\+\{2+\} ions, Ca\+\{2+\} ions, Zn\+\{2+\} ions, and Fe\+\{2+\} ions at 1 mmol/L and 5 mmol/L, respectively.

Effects of Exogenous NSP Enzymes(Xylanase, β-glucanase and Cellulase) on Morphology and Functions of Digestive Tract in Growing Pigs Fed with Paddy-Based Diets

Ninety Landrace×Jia 35±0. 40 kg weight growing pigs were randomly allotted to three treatments , each of which was replicated three times with ten pigs per replicate. The pigs were reared on either a conventional corn-based diet (control I ) or a paddy-based diet (control I ) or a paddy diet supplemented with 0.2% NSP enzymes (test group). All pigs were given ad libitum access to both feed and water. The results of feeding trial showed that supplementation of NSP enzymes significantly increased ADG by 8.78% (P< 0.05) and decreased F/G by 9. 42% (P<0. 05) over the control group Ⅱ. No significant differences were found in ADG and F/G between control group I and the test group. The digestive trial showed that adding NSP enzymes significantly improved apparent digestibility of CP, EE and CF by 18. 76 (P<0. 01), 16.04 (P <0.05) and 108. 57%(P<0. 05), respectively, compared to control Ⅱ. The activities of proteolytic enzyme and α-amylase in duodenal contents were increased by 99. 07 (P<0. 01) and 18. 41% (P<0. 05) with the addition of NSP enzymes. No significant differences between test and control Ⅱ group were found in activities of the pepsin in the gastric content, the trypsin and lipase in duodenal contents. the disaccharidase and y-glutany transferase (γ-GT) in intestinal mucosa, but there was a tendency towards higher activities associated with the NSP enzymes diet(P>0. 05). The lengths of the villi within the duodenal, jejunal and ileal sections of the small intestine of pigs receiving the NSP enzymes diet were increased by 23. 68 (P<0. 05), 56. 00 (P<0. 01) and 76. 90%(P<0. 01) respectively, relative to the pigs in controlⅡ.

Effects of nitrogen ion irradiation on endoglucanase activity and gene mutation of Bacillus subtilis Bac01

Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.

Changes in Protein Content and Chitinase and β-1,3- glucanase Activities of Rice with Blast Resistance Induced by Ag-antibiotic 702

[Objective] The paper was to explore the effect of rice blast resistance induced by Ag-antibiotics 702 on protein content and chitlnase and β-1,3-glucanase activities in rice. [ Method] At the fourth leaf stage of Luliangyou 996, 15 μg/mL Ag-antibiotic 702 was sprayed, while Validamycin and distilled wa- ter were sprayed as positive control and negative control, respectively. All treatments were inoculated with spore fluid of Magnaporthe grisea at 48 h post spraying, and the rice inoculated with only distilled water was used as blank control. The enzymes activities （endochitinase, exochitinase and β-1,3-glucanase） and total pro- tein content in rice leaves were determined every 24 h within 168 h post spraying. [ Result] Compared with the blank control, the rice inoculated with spore fluid of M. grisea could significantly increase the total protein content and the activities of β-1,3-glucanase and chitinase. The induction effect of Ag-antibiotics 702 exceeded that of Validamycin treatment. And the changes in activities of β-1,3-glucanase and chitinase had obvious synchronicity. [ Conclusion] Ag-antibiotic 702 can significantly improve the total protein content and the activities of β-1,3-glucanase and chitinase, thus enhancing the resistance to rice blast.

Cultivar and Environmental Effects on p-glucanase Activity in Both Barley Grain and Malt and Its Function in β-glucan Degradation

Eight two-rowed barley cultivars were grown at seven locations in the southern winter-barley zone of China. Mean grainβ-glucanase activity ranged from 39.89 U kg-1 for Suyin2 to 49.75 U kg-1 for Xi-umai3 in 8 cultivars grown at 7 locations, and from 38. 74 U kg-1 in Zhengzhou to 57. 96 U kg-1 in Putian among 7 locations on an average of all cultivars. Correspondingly, mean malt β-glucanase activity of 8 cultivars ranged from 313.33 U kg-1 for ZAU3 to 489. 89 U kg-1 for Daner Barley, and of 7 locations from 330.40 U kg-1 in Yancheng to 418. 24 U kg-1 in Putian. There were significant differences among cultivars and locations in maltβ-glucanase activities. The locations showed much larger variation in maltβ-glucanase activities than cultivars. The reduction of total β-glucan content after malting varied in both cultivars and locations, with a mean of 78.31%. The analysis of correlations showed that maltβ-glucan content was significantly positively and negatively correlated with grain β-glucan content and malt β-glucanase activity, respectively, and malt β-glucanase activity was significantly positively correlated with grain β-glucanase activity.

Cloning and Bioinformatics Analysis of Rosa rugosa β-1,3-Glucanase Gene (RrGlu)

In order to reveal which role the callose played in R. rugosa pollination incompatibility, the full-length cDNA sequence of β-1,3-glucanase gene was cloned for the first time from the stylus of Rosa rugosa “Tanghong” with RT-PCR and RACE methods and named as RrGlu. The full-length cDNA is 1380 bp with an open reading frame of 1041 bp, encoding 346 amino acids. The derived protein has a molecular weight of 37.85 kD, a calculated pI of 9.12, a pfam00332 conserved domain at position 36 - 345, and belongs to glycosyl hydrolase family 17. The derived protein is a hydrophilic protein secreted into the vacuole. There is a signal peptide cleavage site at position 34 - 35, a transmembrane domain at position 13 - 32, six Ser phosphorylation sites, three Thr phosphorylation sites, three Tyr phosphorylation sites, one N-glycosylation site, and five O-glycosylation sites. There are 31.50% α-helixes, 30.92% random coil, 25.14% extended peptide chain, and 12.43% β-corner structure. This protein and the Glu protein from eight other species, including Prunus persica, share a sequence homology of greater than 72%;all of the proteins contain a pfam00332 conserved domain and a β-1,3-glucanase active center sequence (LIVM)-X-(LIVMFYW)3-(STAG)-E-(ST)-G-W-P-(ST)-X-G. Furthermore, their phylogenetic relationships are consistent with their traditional classifications. These results were meaningful to reveal the molecular mechanism of R. rugosa pollination incompatibility and improve the theory and techniques of breeding ornamental R. rugosa.

Expression Vector Construction and Genetic Transformation of <i>Rosa rugosa β</i>-l,3-Glucanase Gene (<i>RrGlu</i>)

In order to lay a foundation for researching the function of Rosa rugose (R. rugosa) RrGlu gene, the RrGlu gene was amplified from the styles of R. rugosa “Tanghong”, a gene expression vector named PBI121-RrGlu was constructed and the vector was introduced into tobacco with the agrobacterium-mediated method. PCR results showed that the RrGlu gene was integrated into the tobacco genome.

Measurement of β-1,3 Glucanase Activity in Permeabilized Discs of Leaves of Healthy and Scald-Diseased Plants

Leaf discs of five cultivars of sugarcane exhibiting different degree of susceptibility to leaf scald were used to measure β-1,3 glucanase activity before and after experimental infection with Xanthomonas albilineans. Leaf discs were permeabilized with iso-propanol to facilitate the uptake of the enzyme substrate by intact tissues and to improve the enzyme assay. Bacterial infection significantly enhances β-1,3 glucanase activity of sensitive cultivars whereas significantly decreased that of the resistant one. Low concentrations of salicylate increase the hydrolase activity whereas jasmonic acid do not act as an elicitor of the enzyme and β-1,3 glucanase, such as laminarin, significantly inhibits the production of β-1,3 glucanase. Thus, the enzyme must be considered as a sensitivity factor induced by the pathogen.

Characterization of dual enzyme resulted from bicistronic expression of two β-glucanases in porcine cells

Many animal feed grains contain high β-glucan in the cell wall. Pigs do not secret β-glucanase to degrade the β-glucan in their feed. The indigestible β-glucan not only blocks the release of nutrients from the grain cell wall, but also increases the digesta viscosity in the gastrointestinal tract of pigs. Therefore, dietary β-glucan significantly inhibits nutrient digestion and absorption in pigs. Transgenic expression of β-glucanase in the digestive tract of pigs may offer a solution to solve this problem. In the current study, four artificial codon-optimized β-glucanases genes was prepared and expressed in porcine cells. Only p Bg A and p Egx showed high activity in transfected pig kidney cells. To improve the p H range and p H stability of β-glucanase, the two β-glucanases, p Bg A and p Egx, were co-expressed in pig kidney cells and salivary gland cells by Linker A3 or 2A peptide. The resulting dual enzymes of p Bg A3 p Eg and p Bg2 Ap Eg showed significantly enlarged p H range and significantly increased p H stability, as compared to parental enzymes. These results provide useful data for future study on increasing the feed digestibility of pigs by transgenic expression of β-glucanase in their salivary glands.

Cloning and Expression of Extremely Heat-Resistant Endo-β-1,4-Glucanase Gene from Thermotoga maritima in Bacillus subtilis

Gene encoding endo-β-1,4-glucanase(TM1525)is derived from Thermotoga maritima(T.maritima),which has an open reading frame of 825 bp and encodes a 274 amino acid endo-β-1,4-glucanase.This enzyme has the same high temperature resistance as thermophilic bacteria,which is an ideal property for industrial applications.By molecular biological means,TM1525 was cloned into pHT43 vector and introduced into Bacillus subtilis(B.subtilis)WB800N by electroporation.The results showed that the WB800N expression system was successfully constructed,and extracellular expression of the recombinant gene was achieved.Cellulose hydrolyzed activity of the protein was exhibited.

Purification and Some Properties of Endo-1,4-β-Glucanases of Trichoderma harzianum UzCF-28

This work aimed at isolation, purification and study of biochemical features of cellulolytic enzymes synthesized by Trichoderma harzianum UzCF-28 strain. Strain UzCF-28 revealed a high cellulolytic activity during submerged cultivation in the liquid culture on modified Mandels nutrient medium, where wheat straw was used as a source of carbon. As a result of purification by precipitation with ammonium sulfate and further ion exchange chromatography, two isoforms of endo- 1,4-β-glucanase-EG II and EG III with molecular weight of 135 and 75 kDa respectively were revealed. The pH optimum for EG I and EG III was 4.5, while for EG II—4.7, irrespective of the applied substrates—either CMC or “Whatman filter” paper. Heating up to 40°C of EG III did not lead to its inactivation, and on the contrary, its activity increased by more than three times comparing to the initial activity of the enzyme, i.e. thermostability of EG III among tested enzymes significantly varied.

哈茨木霉β-葡聚糖酶诱导、纯化及对黄瓜幼苗的促生防病作用

在实验室条件下分别以β-葡聚糖、麦麸和黄瓜枯萎病菌(Fusarium oxysporum)细胞壁作为唯一碳源诱导哈茨木霉菌(Trichoderma harzianum)Th-30发酵产生β-葡聚糖酶,采用硫酸铵盐析和琼脂糖凝胶色谱柱层析法对β-葡聚糖酶进行分离纯化,以津研4号黄瓜为试验材料,探究β-葡聚糖酶对黄瓜幼苗抗性生理指标、形态指标的影响及黄瓜常见土传病害的防控作用。结果表明:不同诱导条件下木霉Th-30发酵产β-葡聚糖酶活性差异显著,经β-葡聚糖诱导发酵的粗酶液酶活性最高,发酵72 h时达75.63 U·mL^(-1);纯化的β-葡聚糖酶比活力为783.56 U·mg^(-1),是粗酶液的45.32倍;5倍液和10倍液β-葡聚糖酶可显著提高黄瓜幼苗的根系活力、游离脯氨酸含量、苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)活性以及根冠比和壮苗指数;β-葡聚糖酶10倍液处理对黄瓜立枯病、黄瓜枯萎病、黄瓜疫病、黄瓜猝倒病、黄瓜菌核病的防效为50.36%~80.63%。

哈茨木霉UN⁃2β⁃葡聚糖酶诱导及对水稻纹枯病的抑菌防病作用

【目的】优化哈茨木霉UN⁃2菌株产β⁃葡聚糖酶的培养基组分及发酵参数,提高其产酶能力,研究β⁃葡聚糖酶粗酶液对水稻纹枯病病原菌的拮抗作用及田间防效,阐明哈茨木霉菌株UN⁃2在水稻纹枯病生物防治中的应用潜力。【方法】采用单因素试验考察不同碳源、氮源和金属离子对哈茨木霉菌株UN⁃2产β⁃葡聚糖酶的影响,利用正交试验确定木霉菌株产β⁃葡聚糖酶的最适温度、pH、接种量、瓶装量、摇床转速和发酵时间,优化哈茨木霉菌株UN⁃2产β⁃葡聚糖酶诱导发酵条件;通过体外拮抗试验和田间防效试验研究β⁃葡聚糖酶粗酶液对水稻纹枯病的抑菌防病作用。【结果】哈茨木霉菌株UN⁃2发酵产β⁃葡聚糖酶最佳碳源和氮源分别为麦麸和硫酸铵,金属离子Ca^(2+)和Mg^(2+)对木霉产β⁃葡聚糖酶活性具有明显的促进作用。哈茨木霉UN⁃2菌株以10.0 g/L麦麸、0.5 g/Lβ⁃葡聚糖、4.0 g/L硫酸铵、1.5 mmol/L Ca^(2+)、0.5 mmol/L Mg^(2+)为培养基,在温度32℃、起始pH 6.5、接种量8 mL(10^(6) cfu/mL)、瓶装量30 mL/250 mL、摇床转速160 r/min条件下发酵64 h获得β⁃葡聚糖酶活性最高。木霉菌株UN⁃2产β⁃葡聚糖酶粗酶液对立枯丝核菌和禾谷丝核菌的菌丝生长和菌核萌发具有明显的抑制作用,对由立枯丝核菌引起的水稻纹枯病的田间防效达70.45%,与5%井冈霉素处理相当,β⁃葡聚糖酶粗酶液处理可提高水稻结实率和稻粒充实度。【结论】哈茨木霉菌株UN⁃2在最优发酵条件下产酶活性达97.68 U/mL,β⁃葡聚糖酶粗酶液对水稻纹枯病具有较强的抑菌防病效果,并对水稻植株具有一定的促生作用。

黑曲霉耐热型葡聚糖酶纤维素结合结构域的替换与融合体酶性质

该文旨在通过更换纤维素结合结构域(cellulose binding domain, CBD)的方式探索获得具有纤维素水解能力的耐热型葡聚糖酶的方法。黑曲霉(Aspergillus niger)来源的葡聚糖酶AnEglA6具有优越的耐热性能,在禽类饲料生产中具有应用前景。通过更换不同家族来源的碳水化合物结合结构域(carbohydrate binding module, CBM)编码区,构建了融合体葡聚糖酶基因,分别在巴斯德毕赤酵母(Pichia pastoris)中进行异源表达。AnEglA6催化结构域与分别来源于嗜热菌(Caldicellulosiruptor kristjanssonii)和荧光假单胞菌(Pseudomonas fluorescens)的木聚糖酶的底物结合结构域CBM9、CBM10结合获得的融合体酶AnEg-CBM9和AnEg-CBM10均具有较高的纤维素水解能力,并且底物范围进一步扩大,对微晶纤维素也具有一定的水解能力。AnEg-CBM10热稳定性有显著的提高,在85℃下酶活力半衰期达到40 min左右,能短时耐受90℃高温。融合体酶AnEg-CBM10是一种热稳定性提高、具有纤维素水解能力的新型葡聚糖酶。

湖羊瘤胃微生物来源的低温葡聚糖酶的表达与功能表征

葡聚糖酶作为添加剂在饲料、食品和纺织工业中具有重要的应用价值。本研究从湖羊瘤胃微生物c DNA中扩增IDSGH5-50基因,通过大肠埃希菌BL21(DE3)进行异源表达,研究重组蛋白rIDSGH5-50的酶学性质和水解产物。结果表明:IDSGH5-50编码690个氨基酸,蛋白质分子量为75.78 kDa,等电点为4.75;重组蛋白rIDSGH5-50的最适反应条件为温度30℃、pH 6.0,且能在4~20℃下保持较高活性(>70%),在pH 5.0~8.0范围内稳定性较高。rIDSGH5-50的活性底物谱分析显示,rIDSGH5-50能催化大麦β-葡聚糖、地衣多糖、罗望子木葡聚糖和魔芋胶,对应的比活性分别为(10.42±0.16)、(7.12±0.08)、(7.03±0.38)、(5.94±0.65) U/mg。薄层色谱分析表明,在rIDSGH5-50催化下,大麦β-葡聚糖主要降解成纤维四糖和纤维五糖,地衣多糖主要降解成纤维三糖和纤维五糖,魔芋胶主要降解成纤维五糖,罗望子木葡聚糖主要降解成聚合度>5的寡糖。本研究报道了一种来自瘤胃球菌属的低温内切β-1,4-葡聚糖酶IDSGH5-50,为饲料、食品酶制剂开发奠定了基础。

食品级商业酶转化人参皂苷Rb1制备人参皂苷Rd研究

在11种不同厂家食品级商业酶中筛选出转化人参皂苷Rb1制备Rd活性最佳的酶,并利用单因素实验考察反应时间、酶量、初始pH及温度对转化效率的影响。结果显示,β-葡聚糖酶(庞博)的转化活性最高,其最佳转化条件为反应时间2 h,酶量0.3 mg/1.5 mg Rb1,pH 5.5和55℃,Rd转化效率为98.01%±1.19%(n=3)。β-葡聚糖酶(庞博)酶转化法是一种高效、绿色、安全的人参皂苷Rd制备方法。

β-1,3-葡聚糖内切酶合成、制备及应用研究进展

β-1,3-葡聚糖内切酶是一类广泛存在于细菌、真菌和某些植物中,并能够水解β-葡聚糖产生不同分子量葡聚糖的酶。低分子量葡聚糖具有抗菌、抗氧化、免疫调节和抗肿瘤的生理活性,已在医药、食品、化工等多个领域显现良好的应用前景。目前生产低分子量葡聚糖的方法主要包括物理、化学和酶降解法。相较于物理和化学降解法,酶降解法具有催化效率高、反应条件温和、收率高及对环境友好等特点,但现阶段已开发的β-1, 3-葡聚糖内切酶的酶活性和稳定性仍无法满足工业化生产的需求。因此,开发适用于工业化生产的β-1,3-葡聚糖内切酶,已成为跨越通过降解高分子量葡聚糖制备低分子量葡聚糖技术壁垒的关键。本文系统介绍了β-1,3-葡聚糖内切酶的合成调节、特点、用于低分子量葡聚糖的制备以及工艺的优化等方面的研究进展,为促进β-1,3-葡聚糖内切酶的研究和工业化应用提供参考。

β-葡聚糖酶高产菌株诱变选育

以木霉(Trichoderma sp.)为出发菌株,通过紫外诱变与光复活交替处理获得了1株高产β-葡聚糖酶突变株UN123。该菌株在摇瓶中的平均酶活大于10000 U/mL,最适反应温度是40℃,90℃条件下保温处理2 h,仍能保持80%以上酶活,最适反应pH是3.0,在pH 2.0~7.0的条件下处理2 h后,相对酶活力保持在80%以上且对胃蛋白酶、胰蛋白酶及凝乳蛋白酶具有良好的耐受性。