Metagenomic mining of feruloyl esterases from termite enteric flora

Abstract

A metagenome expression library was created from Trinervitermes trinervoides termite hindgut symbionts and subsequently screened for feruloyl esterase (FAE) activities, resulting in seven recombinant fosmids conferring feruloyl esterase phenotypes. The amino acid sequence lengths of the seven FAE encoding open reading frames (ORFs) ranged from 260 to 274 aa and encoded polypeptides of between 28.9 and 31.4 kDa. The highest sequence identity scores for the seven ORFs against the GenBank database were between 45 and 59 % to a number of carboxyl ester hydrolyses. The seven FAE primary structures contained sequence motifs that correspond well with a classical pentapeptide (G-x-S-x-G) serine hydrolyse signature motif which harbours the catalytic serine residue in other FAE families. Six of the seven fae genes were successfully expressed heterologously in Escherichia coli, and the purified enzymes exhibited temperature optima range of 40-70 °C and the pH optima of between 6.5 and 8.0. The k(cat)/K(M) ratios for the six characterised FAEs showed the following order of substrate preference: methyl sinapate > methyl ferulate > ethyl ferulate. All six FAEs showed poor conversion rates against methyl p-coumarate and methyl caffeate, both of which lacked the methoxy (O-CH₃) group substituent on the aromatic ring of the ester substrates, emphasising the requirement for at least one methoxy group on the aromatic ring of the hydroxycinnamic acid ester substrate for optimal FAE activity.

Characterization of the bacterial community in different parts of the gut of sea cucumber (Apostichopus Japonicus ) and its variation during gut regeneration

“…As different parts of the gut have different functions, their corresponding microbial structures and functions will change as well, which has been proven in the human body, chicken, mice and insects (Rashamuse et al., ; Rehman, Vahjen, Awad & Zentek, ; Stachler & Bibby, ; Warnecke et al., ). In this study, the metagenomic sequencing technology was used to analyze the diversity of bacterial community in the gut in different parts of the gut of sea cucumber ( A. japonicus ) and predict the biological functions.…”

“…to study the abundance and diversity of the bacterial community in the gut (Table 4). The results indicated that the abundance and diversity of bacterial community in the gut during the earlier regeneration stage were on a rising trend, reached a peak during the 15th As different parts of the gut have different functions, their corresponding microbial structures and functions will change as well, which has been proven in the human body, chicken, mice and insects (Rashamuse et al, 2014;Rehman, Vahjen, Awad & Zentek, 2007;Stachler & Bibby, 2014;Warnecke et al, 2007). In this study, the metagenomic sequencing technology was used to analyze the diversity of bacterial community in the gut in different parts of the gut of sea cucumber (A. japonicus) and predict the biological functions.…”

An unusual feruloyl esterase belonging to family VIII esterases and displaying a broad substrate range

“…EstG34 had a specific activity of 10.3 U mg -1 , 0.65 U mg -1 and 0.11 U mg -1 on these substrates, respectively (Supplementary Figure S4). While there are relatively few characterised feruloyl esterases in the literature [43,44,45] EstG34 activity is comparable to two characterised fungal feruloyl esterases [46].…”

Neotropical termite microbiomes as sources of novel plant cell wall degrading enzymes

“…N. aquilinus feeds exclusively on wood, whereas C. fulviceps consumes more nitrogen rich organic matter, including either living or decaying plant tissues 84,85 . This difference in diet may explain the metabolic pathway profiles of each termite colony.…”