Combined pretreatments of coffee silverskin to enhance fermentable sugar yield

  • Saverio Niglio
  • Alessandra Procentese
  • Maria Elena RussoEmail author
  • Giovanni Sannia
  • Antonio Marzocchella
Original Article


A huge amount of lignocellulosic agro-food processing wastes (AFWs) is produced by agricultural practices and food industries. Coffee silverskin (CSS) is an AFW produced during the coffee bean–roasting process. Pretreatment methods are required to promote the enzymatic hydrolysis of AFWs, including CSS, aimed at their use as feedstock in a sugar-based biorefinery. A combined pretreatment, based on ultrasound and mild alkaline solution, has been optimized for CSS. The effects of sonication time, biomass loading, NaOH concentration and alkaline pretreatment residence time were investigated according to the response surface methodology. The maximum sugar yield (YS = 0.6 g g sugars in pretreated CSS−1) was obtained after enzymatic hydrolysis of CSS pretreated with 5-min sonication at 11% w v−1 biomass loading, and 75-min autoclave in 5% w v−1 NaOH. Fermentation inhibitors in the pretreatment solvent were absent or present at concentrations not affecting the growth of Clostridium sp. relevant for biofuel production. The phenolic content was 25 mgGAE graw_CSS−1.


Biorefinery Lignocellulose Coffee silverskin Ultrasound Alkaline pretreatment 



Luciano Cortese is gratefully acknowledged for performing scanning electron microscopy analysis.

Funding information

The present work has been partially funded by the European Union’s Horizon 2020 research and innovation program with the grant agreement no. 654623 “Waste2Fuels - Sustainable production of next generation biofuels from waste streams.”


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Dipartimento di Ingegneria Chimica dei Materiali e della Produzione IndustrialeUniversità degli Studi di Napoli Federico IINaplesItaly
  2. 2.Istituto di Ricerche sulla Combustione - Consiglio Nazionale delle RicercheNaplesItaly
  3. 3.Dipartimento di Scienze ChimicheUniversità degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant’AngeloNaplesItaly

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