Feruloyl esterases

The same enzyme (RGAE) could be purified from A. niger, together with two other esterases a feruloyl esterase (FAE) and an acetyl esterase (PAE) specific for the removal of one type of acetyl group present in the smooth regions of sugar-beet pectin. 

Xylans are heteropolysaccharides which are depolymerized by j8-l,4-D-endoxylanases. Due to the abundance and variety of substituents in native xylans, different accessory enzymes are also needed for the total hydrolysis of xylan. The knowledge of a-glucuronidase, a-arabinosidase, and acetyl xylan- and feruloyl esterases has increased considerably in recent years. In addition to acting in synergism with endoxylanases and )8-xylosidase for the complete hydrolysis of xylan, some of these accessory enzymes are also capable of changing the structure of polymeric xylans. 

Feruloyl esterase activity was first detected in culture filtrates of Strepto-myces olivochromogenes (49), and has thereafter also been reported for some hemicellulolytic fungi (Table III). A partially purified feruloyl esterase from S. commune liberated hardly any ferulic acid without the presence of xylanase (65). Very recently a feruloyl esterase was purified from Aspergillus oryzae (Tenkanen, M. Schuseil, J. Puls, J. Poutanen, K., /. Biotechnol, in press). The enzyme is an acidic monomeric protein having an isoelectric point of 3.6 and a molecular weight of 30 kDa. It has wide substrate specificity, liberating ferulic, p-coumaric, and acetic acids from steam-extracted wheat straw arabinoxylan. 

The late discovery of acetyl xylan and feruloyl esterases has been partly due to the lack of suitable substrates. Xylans are often isolated by alkaline extraction, in which ester groups are saponified. Treatment of plant materials under mildly acidic conditions, as in steaming or aqueous-phase thermomechanical treatment, leaves most of the ester groups intact. These methods, however, partly hydrolyze xylan to shorter fragments (63,69). Polymeric acetylated xylan can be isolated from delignified materials by dimethyl sulfoxide extraction (70). The choice of substrate is especially important in studies of esterases for deacetylation of xylans. The use of small chromophoric substrates (p-nitrophenyl acetate, a-naphthyl acetate, and methylumbelliferyl acetate) analogously to the assays of disaccharidases may lead to the monitoring of esterases unable to deacetylate xylan (33, 63, 64). 

Mathew S, Abraham TE (2004) Eerulic acid an antioxidant found naturally in plant cell walls and feruloyl esterases involved in its release and their applications. Grit Rev Biotechnol 24 59-83... 

Topakas, E., H. Stamatis, P. Biely, D. Kekos, B J. Macris, and P. Christakopoulos. 2003. Purification and characterization of a feruloyl esterase from Fusarium oxysporum catalyzing esterification of phenolic acids in ternary water-organic solvent mixtures. J. Biotechnol. 102 33-44. 

EC 3.1.1.73 feruloyl esterase feruloyl-polysaccharide + H20 = ferulate + polysaccharide... 

It is accepted that yeasts only metabolise the free acid forms, although brewing S. cerevisiae was supposed to possess feruloyl esterasic activity (Coghe et al. 2004). Then the availability of free hydroxycinnamic acids appears to be crucial for the production of VPs either by yeasts or bacteria. 

Coghe, S., Benoot, K., Delvaux, F., Vanderhaegen, B. and Delvaux, F.R. (2004) Ferulic acid release and 4-vinylguaiacol formation during brewing and fermentation indications for feruloyl esterase activity in Saccharomyces cerevisiae, J. Agric. Food Chem., 52(3), 602-608. 

Mandalari, G., Bisignano, G., Lo Curto, R. B., Waldron, K. W., and Faulds, C. B. (2008). Production of feruloyl esterases and xylanases by Talaromyces stipitatus and Humicola grisea var. thermoidea on industrial food processing by-products. Bioresour. Technol. 99, 5130-5133. 

Bonnin, E. et al., Aspergillus niger 1-1472 and Pycnoporus cinnabarinus MUCEL 39533, selected for the biotransformation of ferulic acid to vanillin, are also able to produce cell wall polysaccharide-degrading enzymes and feruloyl esterases, Enzyme Microb. Technol, 28, 70, 2001. 

Vafiadi C, Topakas E, Nahmias VR, Faulds CB, Christakopoulos P (2009) Feruloyl esterase-catalysed synthesis of glycerol sinapate using ionic liquids mixtures. J Biotechnol 139 124-129... 

CE Family 1 is very large and contains members which do not act on carbohydrate-derived substrates. The crystal structure of a CE 1 domain of XynlOB modular enzyme from Clostridium thermocellum has been solved. " The CE 1 domain is a feruloyl esterase which hydrolyses the feruloyl groups attached to some arabinofuranosyl 05 groups in native xylan. (The Xyn lOB protein as a whole consists of two CBM 22 domains, a dockerin domain, and a GH 20 xylanase domain, and forms part of a cellulosome - see Section 5.10.) The enzyme has the common a/p hydrolase fold. Studies of ferulic acid complexes of the inactive alanine mutant of the active site serine revealed the classic catalytic triad, and two main-chain peptide NH bonds are in place to form an oxyanion hole . A remarkable feature is that the enzyme as repeatedly isolated was esterilied on the active site serine by phosphate or sulfate. 

Over-expression in E. coli. The reading frame of fae-1 was expressed in E. coli using the pET expression system. Various temperatures and IPTG concentrations were tested to find the best conditions in order to produce the largest quantity of soluble protein. However, the recombinant feruloyl esterase proved to be insoluble (Figure 3) and non-active irrespective of the conditions employed. 

Five transformants produced a major secreted protein band, with an estimated molecular weight of 40 kDa and no protein was detected in the control. The estimated molecular weight is greater than that predicted or observed from E. coli, which is likely due to post-translational modification. P6 and P10 transformants were retained to perform enzymatic assays. The culture supernatants were assays for activity against methyl caffeate (MCA) and methyl ferulate (MFA). The recombinant proteins were shown to be active as a feruloyl esterase and show the characteristics of a type B ferulic acid esterase.6 Feruloyl esterase activity is reported in Table 1. 

The identification of a type B feruloyl esterase from N. crassa was based on (1) the homology found between the peptide sequence of a P. funiculosum type B feruloyl esterase and the translation of N. crassa fae-1 gene (2) the gene was... 

Table 1 Feruloyl esterase activity ofP. pastoris culture supernatants...

The amount of reducing sugars released by the enzyme mixture from H. jecorina (after 8 days incubation with untreated bermudagrass) individually or in combination with feruloyl esterase was 72.1 and 84.8%, respectively, of the Spezyme CP preparation... 

Considering that the microorganism source for the Spezyme CP enzyme preparation is also H. jecorina, our results using a different approach confirm previous work showing that low molecular weight phenolic compounds are inhibitory to the action of cellulases from H. jecorina. Vohra et al. [35] demonstrate that at least some of H. jecorina cellulases are inhibited in the presence of different concentrations of ferulic acid. H. jecorina itself does not produce feruloyl esterase activity [12], so it may not be surprising that the cellulases do not seem to act in synergism with feruloyl esterases and are inhibited by the esterase... 

Regioselectively protected cytidine derivatives have been prepared from the peracetylated nucleoside using lipase and esterase reactions. There have been reports on the use of bacterial proteases for the selective acylation of sucrose to produce a variety of different acyl and acrylate esters. 8-Aminooctyl 5-5-coniferyl-5-thio-a-L-arabinofuranoside(27) attached to sepharose proved to be a selective affinity ligand for feruloyl esterase A. niger ... 

Feruloyl esterases have been identified to play a major role in die enzymatic decomposition of cell wall polymers. Both microorganisms and the plant itself produce these enzymes for degradation and cell wall extension purposes respectively. Therefore, feruloyl esterases are diverse in their catalytic properties (12). 

The presence of feruloyl esterase activity was first detected in culture filtrates of Streptomyces olivochromogenes grown on oats spelt xylan and wheat bran (iJ) and have subsequently been found in a number of bacterial and fungal... 

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