A novel method for hydrophobin extraction using CO₂ foam fractionation system

详细信息    查看全文

• 作者：Mohammadreza Khalesi ; Tom Venken ; Sylvie Deckers ; James Winterburn ; Zahra Shokribousjein ; Kurt Gebruers ; Hubert Verachtert ; Jan Delcour ; Peter Martin ; Guy Derdelinckx
• 关键词：Hydrophobin ; Foam fractionation ; CO2 ; Fermentation ; Gushing
• 刊名：Industrial Crops and Products
• 出版年：2013
• 出版时间：May, 2013
• 年：2013
• 卷：43
• 期：Complete
• 页码：372-377
• 全文大小：457 K

文摘

Due to the exceptional properties and many potential applications of hydrophobins, special fungal proteins, it becomes necessary to develop a real scale procedure for their production and purification. In our previous study () [CO₂-hydrophobin structures acting as nanobombs in beer, Brew. Sci. 63:54-61], the strong interaction of CO₂-hydrophobin was demonstrated. For the first time, in an approach to isolate hydrophobin HFBII from the growth media of Trichoderma reesei, a foam fractionation system using CO₂ as the sparging gas was investigated in this study. Using CO₂ foam fractionation, the concentration of HFBII was increased from 0.10 ¡À 0.02 mg/mL up to 0.57 ¡À 0.04 mg/mL. This was shown after a purification step by conventional liquid chromatography and identification of the goal protein using MALDI-TOF. The obtained molecular weight of the protein was 7.042 kDa which corresponds to the complete molecule of HFBII, minus the last aminoacid. Micro-spectrophotometry was used for quantification of purified HFBII. Moreover, different parameters of the foam fractionation system were optimized. The concentration of the protein after treatment by CO₂ followed by liquid chromatography was increased from 0.32 ¡À 0.02 to 0.44 ¡À 0.06 mg/mL when the flow rate of gas injection was changed in the range of 1-3 L/min. The highest amount of HFBII equal to 0.57 ¡À 0.04 mg/mL was obtained by the highest ratio of liquid height over the column height. Using the larger pore size frits causes increased protein absorption as well. The gushing potential of samples revealed that in contrast to the samples before CO₂ treatment, interestingly, no gushing was observed for the samples after treatment. The possibility that stable aggregates of HFBII molecules are formed as a consequence of their high concentration is discussed in this paper. By using DLS analysis of the overfoam, 100 nm particle size of CO₂ nanobubbles coated by HFBII was obtained. The final concentration of the protein was carried out using Amicon^? ultracentrifuge device with the average recovery of 63.8 ¡À 8.2 % .