Prospection and Evaluation of (Hemi) Cellulolytic Enzymes Using Untreated and Pretreated Biomasses in Two Argentinean Native Termites

Abstract

Saccharum officinarum bagasse (common name: sugarcane bagasse) and Pennisetum purpureum (also known as Napier grass) are among the most promising feedstocks for bioethanol production in Argentina and Brazil. In this study, both biomasses were assessed before and after acid pretreatment and following hydrolysis with Nasutitermes aquilinus and Cortaritermes fulviceps termite gut digestome. The chemical composition analysis of the biomasses after diluted acid pretreatment showed that the hemicellulose fraction was partially removed. The (hemi) cellulolytic activities were evaluated in bacterial culture supernatants of termite gut homogenates grown in treated and untreated biomasses. In all cases, we detected significantly higher endoglucanase and xylanase activities using pretreated biomasses compared to untreated biomasses, carboxymethylcellulose and xylan. Several protein bands with (hemi) cellulolytic activity were detected in zymograms and two-dimensional gel electrophoresis. Some proteins of these bands or spots were identified as xylanolytic peptides by mass spectrometry. Finally, the diversity of cultured cellulolytic bacterial endosymbionts associated to both Argentinean native termite species was analyzed. This study describes, for the first time, bacterial endosymbionts and endogenous (hemi) cellulases of two Argentinean native termites as well as their potential application in degradation of lignocellulosic biomass for bioethanol production.

Effect of Different Lignocellulosic Diets on Bacterial Microbiota and Hydrolytic Enzyme Activities in the Gut of the Cotton Boll Weevil (Anthonomus grandis)

“…On the other hand, an important decrease in Proteobacteria occurred with CS diets; in this case, we could assign a high number of Spirochaetes OTUs. The same predominant groups have been previously reported in other weevils ( Rhynchophorus ferrugines and Rhynchophorus Vulneratus ), beetles ( Pachisoma endroedyi , Pachisoma striatum , Megetra cancellata , Epicauta longicollis , Gonasida inferna and Calosoma peregrinator ), cotton leafworm ( Spodoptera littoralis ), higher termites ( Nasutitermes aquilinus and Cortaritermes fulviceps ), honey bee ( Apis mellifera ), planthopper ( Lycorma delicatula ) and yellow ladybird ( Illeis koebelei ) (Colman et al, 2012; Shao et al, 2014; Yun et al, 2014; Ben Guerrero et al, 2015; Montagna et al, 2015; Franzini et al, 2016). Furthermore, Spirochaetes have been reported previously as a dominant component of the termite gut microbiota (Warnecke et al, 2007; Husseneder et al, 2010; Boucias et al, 2013; Benjamino and Graf, 2016).…”

“…and Pseudomonas sp.). The genus Acinetobacter was present in the gut of the termite Cortaritermes fulviceps (Ben Guerrero et al, 2015), in the midgut and haemolymph of Leptinotarsa decemlineata , Microcerotermes diversus , and a in the gut of the giant African snail ( Archachatina marginata ). Their cellulase, xylanase and β-glucosidase activities were quantitatively evaluated (Ekperigin, 2007; Pourramezan et al, 2012; Vilanova et al, 2012).…”

“…NG is a perennial grass with a high growth rate (Lima et al, 2014; Ben Guerrero et al, 2015). Corn stover (CS), an abundant biomass residue in corn producing regions can also be used for the production of bioethanol (Kim et al, 2009; Whitman et al, 2011).…”

Sugarcane Bagasse as an Efficient Biosorbent for Methylene Blue Removal: Kinetics, Isotherms and Thermodynamics

“…Fibers are constituted by parallel stripes and are superficially covered with extractives. This continuous covering layer is probably composed of hemicellulose and lignin [16,17].…”

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

“…The specimens were stored at −20 °C until processing. A complete description of the sampling site is reported in Ben Guerrero et al 39 .…”