Application of Two Newly Identified and Characterized Feruloyl Esterases from Streptomyces sp. in the Enzymatic Production of Ferulic Acid from Agricultural Biomass

Abstract

Ferulic acid (FA), a component of hemicellulose in plant cell walls, is a phenolic acid with several potential applications based on its antioxidant properties. Recent studies have shown that feruloyl esterase (FAE) is a key bacterial enzyme involved in FA production from agricultural biomass. In this study, we screened a library of 43 esterases from Streptomyces species and identified two enzymes, R18 and R43, that have FAE activity toward ethyl ferulate. In addition, we characterized their enzyme properties in detail. R18 and R43 showed esterase activity toward other hydroxycinnamic acid esters as well, such as methyl p-coumarate, methyl caffeate, and methyl sinapinate. The amino acid sequences of R18 and R43 were neither similar to each other, nor to other FAEs. We found that R18 and R43 individually showed the ability to produce FA from corn bran; however, combination with other Streptomyces enzymes, namely xylanase and α-l-arabinofuranosidase, increased FA production from biomass such as corn bran, defatted rice bran, and wheat bran. These results suggest that R18 and R43 are effective FAEs for the enzymatic production of FA from biomass.

Multimodular fused acetyl–feruloyl esterases from soil and gut Bacteroidetes improve xylanase depolymerization of recalcitrant biomass

“…The kinetic parameters of FjCE1 on MFA were substantially better than the ones reported for two bacterial FAEs from Streptomyces sp. [27], which had 40-fold higher K M values and around 60-fold lower k cat values. Compared to the fungal FAE AnFaeA, from Aspergillus niger, and the commercial enzyme E-FAERU, from a rumen microorganism, FjCE1 possessed the smallest K M value at 0.11 mM, compared to 0.78 and 0.43 mM for AnFaeA and E-FAERU, respectively [28,29].…”

Loop of Streptomyces Feruloyl Esterase Plays an Important Role in the Enzyme's Catalyzing the Release of Ferulic Acid from Biomass

“…We previously identified two new esterases (R18 and R43) from a Streptomyces esterase library. These esterases showed FAE activity using FA and other cinnamic acid esters as the substrates (11). Both Streptomyces FAEs released FA and diferulic acid from biomass, especially defatted rice bran, in combination with Streptomyces xylanase and arabinofuranosidase (12).…”

Thermotolerant hemicellulolytic and cellulolytic enzymes from Eupenicillium parvum 4-14 display high efficiency upon release of ferulic acid from wheat bran

“…), and has been identified as a key enzyme in releasing FA from plant materials (Uraji et al . ). To date, diverse FAEs were mainly found in fungal species such as Aspergillus niger , Aspergillus usamii , Fusarium oxysporum , Talaromyces stipitatus , Myceliophthora thermophila ( Sporotrichum thermophile ), Anaeromyces mucronatus , Neosartorya spinose and Alternaria alternate , and displayed different efficiencies in releasing FA from agricultural by‐products (Faulds and Williamson ; Shin et al .…”

“…These lignocellulose materials consist of starch and nonstarch polysaccharides (including cellulose and hemicellulose), protein, lignin and diverse phenolic acid compounds. Ferulic acid (4-hydroxy-3methoxycinnamic acid, FA) is a main phenolic acid abundantly existing in the plant cell walls, where it cross-links arabinoxylan molecules via arabinose residues (Uraji et al 2014). As a very attractive phenolic compound, FA can be used as an antioxidant or can be transformed by microbial conversion into 'natural' vanillin, an expensive flavour for food, cosmetic and pharmaceutical industries (Levasseur et al 2005).…”

“…In addition, the enzymatic treatment is more specific for FA and therefore only releases specific products without damaging other valuable chemicals that are destroyed during alkaline extraction (Mathew and Abraham 2004;Gopalan et al 2015). Feruloyl esterases (FAEs, EC 3.1.1.73), a subclass of the carboxylic acid esterases, can catalyse the hydrolysis of ester linkages between FA and polysaccharides (Topakas et al 2007;Gong et al 2013), and has been identified as a key enzyme in releasing FA from plant materials (Uraji et al 2014). To date, diverse FAEs were mainly found in fungal species such as Aspergillus niger, Aspergillus usamii, Fusarium oxysporum, Talaromyces stipitatus, Myceliophthora thermophila (Sporotrichum thermophile), Anaeromyces mucronatus, Neosartorya spinose and Alternaria alternate, and displayed different efficiencies in releasing FA from agricultural by-products (Faulds and Williamson 1995;Shin et al 2006;Topakas et al 2007Topakas et al , 2012Qi et al 2011;Gong et al 2013).…”