In the present study we aimed firstly to assess the resistance of a set of yeasts, isolated from the black olive pomace, to various phenolic compounds; and to evaluate their growth capacities on an olive leaf extract rich of oleuropein. The results showed that only three yeasts were able to both resist to the different phenolic compounds tested and grow on the olive leaf extract at a concentration of 1%. The second step was devoted to studying the bioconversion of oleuropein of an olive leaf extract into hydroxytyrosol by the above selected three yeasts. The oleuropein degradation and hydroxytyrosol formation were monitored by HPLC-UV. Only one yeast isolate; identified using molecular tools; was chosen to optimize the bioconversion throughout the optimization of the most influencing parameters: temperature, substrate concentration, cell concentration, and pH of the extract using a method of experimental design. The results showed that the three yeasts; F6, F4, and F12 were capable of producing hydroxytyrosol from oleuropein with different concentrations 317 ± 14 mg/l, 210 ± 14 mg/l, and 149 ± 21 mg/l; respectively. The strong oleuropienolytic activity manifested by the F6 isolate was further optimized, and the results showed that the optimal conditions for producing the maximum of hydroxytyrosol are: a temperature of 31 °C, a cell concentration of 2%, a substrate concentration of 1%, and a non-adjusted pH of the extract. Based on the molecular approaches F6 was identified as Nakazawaea molendini-olei.

在本研究中，我们的目标是首先评估从黑橄榄果渣中分离出的一组酵母对各种酚类化合物的抗性；并评估其在富含橄榄苦苷的橄榄叶提取物中的生长能力。结果表明，只有三种酵母能够同时抵抗不同的酚类化合物，并在橄榄叶提取物中以1％的浓度生长。第二步致力于研究通过以上选择的三种酵母将橄榄叶提取物的橄榄苦苷生物转化为羟基酪醇。通过HPLC-UV监测橄榄苦苷的降解和羟基酪醇的形成。只有一种酵母菌分离物；使用分子工具鉴定；在整个影响最大的参数（包括温度，底物浓度，细胞浓度和提取液的pH使用实验设计方法。结果显示三种酵母；F6，F4和F12能够从橄榄苦苷生产浓度为317±14 mg / l，210±14 mg / l和149±21 mg / l的羟基酪醇；分别。进一步优化了由F6分离物表现出的强油橄榄烯分解活性，结果表明，产生最大量的羟基酪醇的最佳条件为：温度31°C，细胞浓度2％，底物浓度1％，萃取液的pH值未调整 根据分子方法，F6被确定为 F12和F12可以从橄榄苦苷生产浓度为317±14 mg / l，210±14 mg / l和149±21 mg / l的羟基酪醇。分别。进一步优化了由F6分离物表现出的强油橄榄烯分解活性，结果表明，产生最大量的羟基酪醇的最佳条件为：温度31°C，细胞浓度2％，底物浓度1％，萃取液的pH值未调整 根据分子方法，F6被确定为 F12和F12能够从橄榄苦苷生产浓度为317±14 mg / l，210±14 mg / l和149±21 mg / l的羟基酪醇。分别。进一步优化了由F6分离物表现出的强油橄榄烯分解活性，结果表明，产生最大量的羟基酪醇的最佳条件为：温度31°C，细胞浓度2％，底物浓度1％，萃取液的pH值未调整 根据分子方法，F6被确定为 底物浓度为1％，萃取液的pH值未调整。根据分子方法，F6被确定为 底物浓度为1％，萃取物的pH值未调整。根据分子方法，F6被确定为Nakazawaea molendini-olei。