Ultrasonic or Microwave Cascade Treatment of Medicinal Plant Waste

Vasile Staicu, Cristina Luntraru, Ioan Calinescu, Ciprian Gabriel Chisega-Negrila, Mircea Vinatoru, Miruna Neagu, Adina Ionuta Gavrila and Ioana Popa
Additional contact information
Vasile Staicu: SC Hofigal Export Import SA, 042124 Bucharest, Romania
Cristina Luntraru: SC Hofigal Export Import SA, 042124 Bucharest, Romania
Ioan Calinescu: Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 1-7 Gh.Polizu St., 011061 Bucharest, Romania
Ciprian Gabriel Chisega-Negrila: Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 1-7 Gh.Polizu St., 011061 Bucharest, Romania
Mircea Vinatoru: Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 1-7 Gh.Polizu St., 011061 Bucharest, Romania
Miruna Neagu: SC Hofigal Export Import SA, 042124 Bucharest, Romania
Adina Ionuta Gavrila: Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 1-7 Gh.Polizu St., 011061 Bucharest, Romania
Ioana Popa: Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 1-7 Gh.Polizu St., 011061 Bucharest, Romania

Sustainability, 2021, vol. 13, issue 22, 1-13

Abstract: In this study, we present a strategy for valorizing lignocellulosic wastes (licorice root and willow bark) that result from industrial extraction of active principles using water as green solvent and aqueous NaOH solution. The wastes were submitted to severe ultrasound (US) and microwave (MW) treatments. The aim of these treatments was to extract the remaining active principles (using water as a solvent) or to prepare them for cellulose enzymatic hydrolysis to hexoses (performed in an NaOH aqueous solution). The content of glycyrrhizic acid and salicin derivatives in licorice root and willow bark wastes, respectively, were determined. The best results for licorice root were achieved by applying the US treatment for 5 min at 25 °C (26.6 mg glycyrrhizic acid/gDM); while, for willow bark, the best results were achieved by applying the MW treatment for 30 min at 120 °C (19.48 mg salicin/gDM). A degradation study of the targeted compounds was also performed and showed good stability of glycyrrhizic acid and salicin derivatives under US and MW treatments. The soluble lignin concentration prior to enzymatic hydrolysis, as well as the saccharide concentration of the hydrolyzed solution, were determined. As compared with the MW treatment, the US treatment resulted in saccharides concentrations that were 5% and 160% higher for licorice root and willow bark, respectively.

Keywords: lignocellulosic waste valorization; licorice root; glycyrrhizic acid; willow bark; salicin derivatives; ultrasound; microwave; enzymatic hydrolysis (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
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Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:13:y:2021:i:22:p:12849-:d:683711

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