Detoxification of hemicellulosic hydrolysates from extracted olive pomace by diananofiltration

Abstract

a b s t r a c tXylitol can be obtained from the pentose-rich hemicellulosic fraction of agricultural residues, such as extracted olive pomace, by fermentation. Dilute acid hydrolysis of lignocellulosic materials, produces the release of potential inhibitory compounds mainly furan derivatives, aliphatic acids, and phenolic compounds. In order to study the potential on the increase of the hydrolysate fermentability, detoxification experiments based on diananofiltration membrane separation processes were made. Two membranes, NF270 and NF90, were firstly evaluated using hydrolysate model solutions under total recirculation mode, to identify the best membrane for the detoxification. NF270 was chosen to be used in the diananofiltration experiment as it showed the lowest rejection for toxic compounds and highest permeate flux. Diananofiltration experiments, for hydrolysate model solutions and hydrolysate liquor, showed that nanofiltration is able to deplete inhibitory compounds and to obtain solutions with higher xylose content. Conversely to non-detoxified hydrolysates, nanofiltration detoxified hydrolysates enabled yeast growth and xylitol production by the yeast Debaryomyces hansenii, clearly pointing out that detoxification is an absolute requirement for extracted olive pomace dilute acid hydrolysate bioconversion.

Olive‐derived biomass as a source of energy and chemicals

“…The production of xylitol from hemicellulosic sugars released from the autohydrolysis of EOP has been investigated. The main conclusion of this investigation was that the detoxification of the liquid phase by nanofiltration was an efficient and essential method required for Debaryomices hansenii to produce xylitol . EOP is also considered to be a raw material in a biorefinery process for ethanol production and other valuable compounds, including proteins, fermentable sugars and lignin, with global recovery values of 10.8, 93.7, and 94.4%, respectively …”

An initial study of EDTA complex based draw solutes in forward osmosis process

“…Four commercial NF membranes listed in Table 1 were used, taking into account the molecular weight of EDTA complexes. Prior to the experiments, Each new membrane was soaked in DI water overnight and compacted with DI water at 20 bar until a constant value of flux was obtained [49]. The pure water permeability of the NF membranes was determined via Eq.…”

Removal of furan and phenolic compounds from simulated biomass hydrolysates by batch adsorption and continuous fixed-bed column adsorption methods

“…These inhibitors include aliphatic carboxylic acids, furans, and phenolic compounds. The removal of such inhibitors has been reported using various separation methods including alkali treatment, vacuum evaporation, activated charcoal adsorption, ion exchange resin adsorption, nanofiltration, and their combinations (Bras et al, 2014;Geddes et al, 2015;Persson et al, 2002;Ra et al, 2015a,b;Santos et al, 2014;Soleimani et al, 2015;Zhang et al, 2015b). However, because these researchers' endeavors have been mostly concerned with completely removing inhibitors in an attempt to improve ethanol yield, the loss of sugar has not been thoroughly considered.…”