Kinetic modelling of the sequential production of lactic acid and xylitol from vine trimming wastes

Abstract

A mathematical model describing the kinetics of the sequential production of lactic acid and xylitol from detoxified-concentrated vine trimming hemicellulosic hydrolysates by Lactobacillus rhamnosus and Debaryomyces hansenii, respectively, was developed from the basic principles of mass balance in two stages considering as main reactions: (1) glucose and xylose consumption by L. rhamnosus; and (2) xylitol and arabitol production by D. hansenii. The model allows to evaluate the yields and productivities under microaerobic and oxygen restricted conditions (in particular the effects caused by purging the oxygen with nitrogen), which were particularly important during the xylose to xylitol bioconversion by yeasts. The model was tested using experimental data obtained from detoxified-concentrated hemicellulosic hydrolysates, after CaCO3 addition in both types of fermentation processes, without purges (microaerobic conditions) or purging oxygen with nitrogen (oxygen-limited conditions) after sampling in order to reduce the oxygen dissolved. L. rhamnosus was removed by microfiltration before adding D. hansenii at the beginning of the second stage. Mass balance-based and logistic functions were successfully applied to develop the model of the system which properly predicts the consumption of sugars as well as the metabolites produced and yields. The dynamics of fermentation were also adequately described by the developed model.

Vineyard pruning waste as an alternative carbon source to produce novel biosurfactants by Lactobacillus paracasei

“…However, most of these applications involve the use of the hemicellulosic fraction rather than the cellulosic sugars. In addition, biosurfactant production by L. paracasei using as carbon source the lignocellulosic residue VPW has not been previously reported [1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…Usually autohydrolysis-posthydrolysis or prehydrolysis (acid hydrolysis) treatments are employed to obtain hemicellulosic sugars (mainly glucose and xylose) from lignocellulosic residues. Several researchers evaluated the use these hydrolysates to produce biosurfactants [1,[4][5][6][7][8], lactic acid [4,6,[9][10][11], xylitol [12][13][14], antioxidants [15], as well as phenyllactic acid [16]. However, the cellulosic fraction obtained after the hydrolysis treatments remains as by-product, probably because its use involves a saccharification process using acids or enzymes.…”

Xylitol production on sugarcane biomass hydrolysate by newly identified Candida tropicalis JA2 strain

“…Yeast species from the Candida , Pichia , Debaryomyces , Kluyveromyces , and Spathaspora genera have been evaluated for xylitol production from biomass hydrolysates. Among these, Candida species have shown good performance with production yields varying from 19% to 72% of the theoretical maximum (Carvalheiro, Duarte, Medeiros, & Gírio, ; García‐Diéguez, Salgado, Roca, & Domínguez, ; Miura et al, ; Rocha et al, ; Rodrigues et al, ; Zhang et al, ). C. tropicalis has shown good performance on lignocellulosic hydrolysates from corncob (Cheng et al, ; Guo et al, ; Ling, Cheng, Ge, & Ping, ; Misra, Raghuwanshi, & Saxena, ; Wang et al, ), rice straw (Liaw, Chen, Chang, & Chen, ), and sugarcane bagasse (Rao, Jyothi, Prakasham, Sarma, & Rao, ).…”

Detoxification of Corncob Acid Hydrolysate with SAA Pretreatment and Xylitol Production by ImmobilizedCandida tropicalis

“…It is well known that mild alkaline pretreatment can remove lignin with little impact on hemicellulose content [13]. Soaking in aqueous ammonia (SAA) has been demonstrated to be a promising pretreatment method of delignification and increase the accessibility of hydrolytic enzymes to cellulose [14]. In our previous work, SAA pretreatment was employed to enhance the fermentation efficiency of rice straw acid hydrolysate for xylitol production [15].…”