An acidic pectin lyase from Aspergillus niger with favourable efficiency in fruit juice clarification

作者：Xu, S. X.; Qin, X.; Liu, B.; Zhang, D. Q.; Zhang, W.; Wu, K.^*; Zhang, Y. H.

来源：Letters in Applied Microbiology, 2015, 60(2): 181-187.

DOI：10.1111/lam.12357

• Aspergillus niger
• juice clarification
• pectin lyase
• Pichia pastoris
• viscosity

The pectin lyase gene pnl-zj5a from Aspergillus niger ZJ5 was identified and expressed in Pichia pastoris. PNL-ZJ5A was purified by ultrafiltration, anion exchange and gel chromatography. The K-m and V-max values determined using citrus pectin were 066mgml(-1) and 326molmin(-1)mg(-1), respectively. PNL-ZJ5A exhibited optimal activity at 43 degrees C and retained activity over 25-50 degrees C. PNL-ZJ5A was optimally active at pH 5 and effective in apple juice clarification. Compared with controls, PNL-ZJ5A increased the fruit juice yield significantly. Furthermore, PNL-ZJ5A reduced the viscosity of apple juice by 388% and increased its transmittance by 863%. PNL-ZJ5A combined with a commercial pectin esterase resulted in higher juice volume.
Significance and Impact of the StudyIn this study, pectin lyase gene pnl-zj5a from Aspergillus niger ZJ5 was expressed successfully in Pichia pastoris. The purified enzyme PNL-ZJ5A exhibited optimal activity at 43 degrees C and pH 5. In addition, the acidic pectin lyase PNL-ZJ5A can effectively decreased the viscosity and improved the yield of apple juice and light transmittance. These favourable enzymatic properties of PNL-ZJ5A show potential application in food industry, especially in juice-processing applications and the extraction of plant tissue.

• 出版日期2015-2
• 单位中国农业科学院; 河南农业大学