Biorefinery of olive leaves to produce dry oleuropein aglycone: Use of homemade ceramic capillary biocatalytic membranes in a multiphase system

Abstract

of olive leaves to produce dry oleuropein aglycone: use of homemade ceramic capillary biocatalytic membranes in a multiphase system,

Production of Plant-Derived Oleuropein Aglycone by a Combined Membrane Process and Evaluation of Its Breast Anticancer Properties

“…As a consequence, the recovered OLA was not purified from the substrate, since unconverted OLE was also present in the collected solution. In the batch system, the co-product glucose also promotes a competitive inhibition, as already reported in Ranieri et al (2018).…”

“…To improve the conversion and purity of OLA, its production was carried out in an MBR consisting of an STR coupled with a UF process. To control the competitive inhibition caused by the co-product glucose ( Ranieri et al, 2018 ), we studied the effect of glucose amount in contact with the enzyme, and its removal by UF ( Table 1 ).…”

“…In this study, the glucose inhibition on the biocatalyst was controlled by adding a higher enzyme amount (enzyme: 1.5 10 −7 mol, substrate: 7.5 10 −5 mol, 2.5 mM) compared to the one previously reported (Ranieri et al, 2018), which achieved a conversion of about 93% in about 5 h in the STR. The same strategy was also used for other enzymatic systems in the presence of competitive inhibition (Andrić et al, 2010).…”

“…The moles of glucose, which were present before the third cycle, are almost doubled (4.6•10 −5 moles) and this causes a significant drop in the degree of conversion (only 22%). To avoid this competitive inhibition, a washing step (with a buffer solution) between the cycles was added (Table 1, SERIE 2) This procedure combined with the new substrate addition allows maintaining the maximum conversion obtained in the first cycle and to overcome the inhibition of the glucose linked to the enzyme since the enzyme has more affinity for the substrate than the inhibitor (K M : 1.17 mM, K i : 1.93 mM, Ranieri et al, 2018). After the washing step (Table 1, SERIE 2) the glucose remained in the retentate solution is washed out, but not the enzyme that thanks to membrane process is retained and can be reused for the next reaction cycle.…”

“…OLA is a vegetal product with many therapeutic applications due to its antihyperglycemic, anti-Alzheimer disease, anti-inflammatory, antioxidant, and other properties ( Galiano and Villalain, 2015 ). In particular, it was produced by the enzymatic (β-glucosidase) hydrolysis of oleuropein (OLE) extracted from olive leaves ( Mazzei et al, 2010b , 2012 ; Ranieri et al, 2018 ; Piacentini et al, 2019 ). In the above-mentioned MBRs, the enzyme was immobilized within the membrane and the maximum conversion achieved was 60%.…”