Integration of galacturonic acid extraction with alkaline protein extraction from green tea leaf residue

Chen Zhang*, Elvira Bozileva, Frits van der Klis, Yiyuan Dong, Johan P.M. Sanders, Marieke E. Bruins

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)


Leaf pectin can be used as a feedstock for galacturonic acid (GA) production, but high extraction costs limit economic feasibility. To improve the extraction efficiency, leaf pectin extraction was integrated with an already cost-effective alkaline protein extraction, focusing on high yield of GA without losses of protein. GA extraction efficiencies in NaOH, HCl, phosphate buffer solution, or with Viscozyme® L were determined using green tea residues (GTR) as model material. Most GA was extracted using Viscozyme® L, mainly due to its cellulase activity. Extraction yielded more than 95% GA with only 5% protein. Alternatively, GA-containing pectin can be extracted in a weak alkaline solution. Here, GA yield is dominated by the ratio of extraction volume to biomass weight. The profits of these two integrated processes can be higher than one step protein extraction. The Viscozyme® L integrated process is suitable for GA production for application in chemicals, and may have a profit of 142$/ton GTR when enzyme cost are sufficiently lowered. The profit of the weak alkaline integrated process is estimated at 118$/ton GTR.

Original languageEnglish
Pages (from-to)95-102
JournalIndustrial Crops and Products
Publication statusPublished - 30 Oct 2016


  • Biorefinery
  • Cellulase
  • Cost estimation
  • Experimental design
  • Leafy biomass
  • Recycle system

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