Food Biotechnology Group, Section of Analytical Environmental and Applied Chemistry, Department of Chemistry, University of Patras, 26500 Patras, Greece.
Appl Biochem Biotechnol. 2012 Jul;167(5):1183-98. doi: 10.1007/s12010-012-9582-2. Epub 2012 Feb 11.
Grape must fermentation performance and volatiles formation by simultaneously cryophilic and thermotolerant yeast (strain AXAZ-1), isolated from grapes in Greece, was evaluated in a wide temperature range (5-40°C). Yeast strain was immobilized on brewer's spent grains (BSG) and the formed biocatalyst was introduced into a Multi-Stage Fixed Bed Tower (MFBT) bioreactor. Almost complete sugar utilization from the aforementioned biocatalyst was observed in a wide temperature spectrum, ranging from 5 °C to 37 °C, while at 40 °C residual sugar was up to 29 g/l. Time to complete fermentation with the immobilized yeast ranged from 290 h at 5 °C and 120 h at 40 °C to 25 h at 33 °C. The daily ethanol productivity reached maximum (88.6 g/l) and minimum (5.6 g/l) levels at 33 °C and 5 °C, respectively. The aroma-related compounds' profiles of immobilized cells at different fermentation temperatures were evaluated by using solid phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS). Must fermentation resulted in a high-quality fermentation product due to the low concentrations of higher and amyl alcohols at all temperatures tested. AXAZ-1 is a very promising strain for quality wine production, as it is capable of performing fermentations of high ethanol concentration and productivities in both low and high temperatures.
从希腊葡萄中分离出的耐冷和耐热酵母（AXAZ-1），在较宽的温度范围内（5-40°C）评估了其葡萄汁发酵性能和挥发性物质的形成。酵母菌株被固定在啤酒糟（BSG）上，形成的生物催化剂被引入多阶段固定床塔式生物反应器（MFBT）中。在较宽的温度范围内（5°C 至 37°C），从上述生物催化剂中观察到几乎完全利用糖，而在 40°C 时残留糖高达 29g/L。用固定化酵母完成发酵的时间范围从 5°C 的 290 小时到 40°C 的 120 小时到 33°C 的 25 小时。固定化细胞在不同发酵温度下的香气相关化合物的特征通过固相微萃取（SPME）气相色谱/质谱（GC/MS）进行了评估。由于在所有测试温度下，高级醇和丙醇的浓度较低，因此固定化细胞的麦芽发酵产生了高质量的发酵产品。AXAZ-1 是一种非常有前途的生产优质葡萄酒的菌株，因为它能够在低温和高温下进行高乙醇浓度和高生产力的发酵。
