Effect of Ash in Paper Sludge on Enzymatic Hydrolysis

Hyeonji Park, David Cruz, Phoenix Tiller, David Johnson, Ashutosh Mittal, Hasan Jameel, Richard Venditti, Sunkyu Park

Research output: Contribution to journalArticlepeer-review

6 Scopus Citations


The valorization of paper sludge is a high-potential process to develop renewable fuels and chemicals, which can be integrated with pulp and paper mills. Calcium carbonate is the main ash component in sludge, which plays a role in buffering pH and potentially lowering the conversion during enzymatic hydrolysis. Therefore, it is important to investigate the effect of ash on sugar yields and examine pH change to introduce efficient and economical enzymatic hydrolysis of sludge. Carbohydrate conversion was enhanced when the ash was removed by fractionation. On the other hand, the highest sugar recovery was obtained when the sludge contained 20% ash content. The pH change during enzymatic hydrolysis was influenced by ash and explained why sludge-derived hydrolysate showed lower carbohydrate conversion. Therefore, a high shear process with the increased acid amount is suggested to prohibit the negative effect of ash and enhance the accessibility of cellulase to fibers. This study highlights the feasibility of using wet waste streams generated by the paper industry.

Original languageAmerican English
Article number106567
Number of pages6
JournalBiomass and Bioenergy
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Ltd

NREL Publication Number

  • NREL/JA-2800-84061


  • Ash
  • Enzymatic hydrolysis
  • Paper sludge
  • Sugars
  • Waste valorization


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