Cherry tree branches (Prunus avium var burlat Rosaceae) are agricultural by-products that are often neglected, yet they are rich in phenolic compounds and highly appreciated for their numerous biological activities. Extracts of cherry tree branches were evaluated for their use in cosmetics, particularly for their antioxidant, anti-tyrosinase, and antimicrobial activities. Samples were obtained by accelerated solvent extraction (ASE) at different ethanol percentages and different temperatures. Fourteen phenolic compounds were identified in the extracts by mass spectrometry. Three major compounds were identified (catechin, genistin, and prunin) representing 84 wt% of the total phenolic compounds. Optimal operating conditions maximizing the content of phenolic compounds were determined using a one factor at a time (OFAT) approach (70% aqueous ethanol, 70 °C). The extract obtained under these conditions also showed the highest antioxidant and anti-tyrosinase activities, certainly due to a high catechin content. Although the antimicrobial activities of extracts are less versatile than those of synthetic molecules, they are nonetheless interesting. According to these results, the extracts of cherry tree branches could be used in cosmetics for their interesting properties.
p-coumaric acid (p-CA) can be produced from D-glucose by an engineered S. cerevisiae strain. p-CA has antimicrobial properties and retro-inhibition activity. Moreover, p-CA is a hydrophobic compound, limiting its accumulation in fermentation broth. To overcome these issues all at once, a liquid-liquid extraction in-situ product recovery process using oleyl alcohol as extractant has been implemented in order to continuously extract p-CA from the broth. Media and pH impacts on strain metabolism were assessed, highlighting p-CA decarboxylase endogenous activity. Biphasic fermentations allowed an increase in p-CA respiratory production rates at both pH assessed (13.65 and 9.45 mg L-1.h-1 at pH 6 and 4.5, respectively) compared to control ones (10.5 and 7.5 mg L-1.h-1 at pH 6 and 4.5, respectively). Biphasic fermentation effects on p-CA decarboxylation were studied showing that continuous removal of p-CA decreased its decarboxylation into 4-vinylphenol at pH 4.5 (57 mg L-1 in biphasic fermentation vs 173 mg L-1 in control one).
Propionates , Saccharomyces cerevisiae , Coumaric Acids , Culture Media , Fermentation
A grass soda technical lignin (PB1000) underwent a process combining solvent fractionation and treatment with an ionic liquid (IL), and a comprehensive investigation of the structural modifications was performed by using high-performance size-exclusion chromatography, 31 Pâ NMR spectroscopy, thioacidolysis, and GC-MS. Three fractions with distinct reactivity were recovered from successive ethyl acetate (EA), butanone, and methanol extractions. In parallel, a fraction deprived of EA extractives was obtained. The samples were treated with methyl imidazolium bromide ([HMIM]Br) by using either conventional heating or microwave irradiation. The treatment allowed us to solubilize 28 % of the EA-insoluble fraction and yielded additional free phenols in all the fractions, as a consequence of depolymerization and demethylation. The gain of the combined process in terms of antioxidant properties was demonstrated through 2,2-diphenyl-1-picrylhydrazyl (DPPH. ) radical-scavenging tests. Integrating further IL safety-related data and environmental considerations, this study paves the way for the sustainable production of phenolic oligomers competing with commercial antioxidants.
