Nuutila A M, Ritala A, Skadsen R W, Mannonen L, Kauppinen V
VTT Biotechnology and Food Research, Espoo, Finland.
Plant Mol Biol. 1999 Dec;41(6):777-83. doi: 10.1023/a:1006318206471.
The malting quality of two barley cultivars, Kymppi and Golden Promise, was modified to better meet the requirements of the brewing process. The egl1 gene, coding for fungal thermotolerant endo-1,4-beta-glucanase (EGI, cellulase), was transferred to the cultivars using particle bombardment, and transgenic plants were regenerated on bialaphos selection. Integration of the egl1 gene was confirmed by Southern blot hybridization. The transgenic seeds were screened for the expression of the heterologous EGI. Under the high-pI alpha-amylase promoter, the egl1 gene was expressed during germination. The heterologous enzyme was thermotolerant at 65 degrees C for 2 h, thus being suitable for mashing conditions. The amount of heterologous EGI produced by the seeds (ca. 0.025% of soluble seed protein), has been shown to be sufficient to reduce wort viscosity by decreasing the soluble beta-glucan content. A decrease in the soluble beta-glucan content in the wort improves the filtration rate of beer.
对两个大麦品种Kymppi和Golden Promise的麦芽品质进行了改良，以更好地满足酿造工艺的要求。编码真菌耐热内切-1,4-β-葡聚糖酶（EGI，纤维素酶）的egl1基因通过粒子轰击转移到这些品种中，并在双丙氨膦选择下再生出转基因植株。通过Southern印迹杂交确认了egl1基因的整合。对转基因种子进行了异源EGI表达的筛选。在高pIα-淀粉酶启动子的作用下，egl1基因在发芽过程中表达。这种异源酶在65℃下能耐2小时高温，因此适合糖化条件。种子产生的异源EGI量（约占种子可溶性蛋白的0.025%）已被证明足以通过降低可溶性β-葡聚糖含量来降低麦芽汁粘度。麦芽汁中可溶性β-葡聚糖含量的降低提高了啤酒的过滤速度。
