Comparative Biochemical Analysis of Cellulosomes Isolated from Clostridium clariflavum DSM 19732 and Clostridium thermocellum ATCC 27405 Grown on Plant Biomass

Abstract

The cellulosome is a supramolecular multienzyme complex formed via species-specific interactions between the cohesin modules of scaffoldin proteins and the dockerin modules of a wide variety of polysaccharide-degrading enzymes. Here, we report a comparative analysis of cellulosomes prepared from the thermophilic anaerobic bacteria Clostridium (Ruminiclostridium) clariflavum DSM 19732 and Clostridium (Ruminiclostridium) thermocellum ATCC 27405 grown on delignified rice straw. The results indicate that the isolated C. clariflavum cellulosome exhibits lower activity for insoluble cellulosic substrates and higher activity for hemicellulosic substrates, especially for xylan, compared to the isolated C. thermocellum cellulosome. The C. clariflavum cellulosome was separated into large and small complexes by size exclusion chromatography, and the high xylanase activity of the intact complex is mainly attributed to the small complex. Furthermore, both C. clariflavum and C. thermocellum cellulosomes efficiently converted delignified rice straw into soluble sugars with different compositions, whereas a mixture of these cellulosomes exhibited essentially no synergy for the saccharification of delignified rice straw. This is the first study to report that isolated C. clariflavum cellulosomes exhibit greater xylanase activity than isolated C. thermocellum cellulosomes. We also report the effect of a combination of intact cellulosome complexes isolated from different species on the saccharification of plant biomass.

Cell‐surface binding domains from Clostridium cellulovorans can be used for surface display of cellulosomal scaffoldins in Lactococcus lactis

“…An additional advantage of using C. cellulovorans as a source of plant-biomass depolymerizing enzymes is that this bacterium can ferment all the main plant polysaccharides (namely cellulose, hemicelluloses and pectins) [19,20] while other cellulolytic microorganisms have more restrained substrate range (e.g., C. thermocellum can metabolize cellulose only [21] and Clostridium cellulolyticum cannot directly use pectin [19] ). Since cellulosome assembly through interaction between scaffoldins and enzyme subunits is generally species-specific, [22] use of C. cellulovorans as cellulase source can provide a larger cellulosomal enzyme panel, without the need of extensive protein engineering. Scaffoldins are pivotal elements of the cellulosome architecture owing to the multiple functions they provide.…”

Expression and Characteristics of Two Glucose-Tolerant GH1 β-glucosidases From Actinomadura amylolytica YIM 77502T for Promoting Cellulose Degradation

“…Most bacteria and fungi hydrolyze cellulose by secreting free cellulases (Cavedon et al, 1990; Ja’afaru, 2013). Meanwhile, a cellulosome is a supramolecular multienzyme complex that can efficiently degrade lignocellulose and is found in just a few bacterial species, including Clostridium ( Ruminiclostridium ) clariflavum and Clostridium ( Ruminiclostridium ) thermocellum (Bayer et al, 2004; Shiratori et al, 2009; Shinoda et al, 2018). As described above, A. amylolytica YIM 77502 T secreted cellulases extracellularly to hydrolyze cellulose.…”

Clostridium thermocellum as a Promising Source of Genetic Material for Designer Cellulosomes: An Overview

“…Therefore, eliminating this feedback inhibition enables an enhanced biomass conversion [41]. The activity of β-glucosidase BglA was found to be too low in WT C. thermocellum strains [42], and due to the adsorption of cellulosomes in cellulose matrix, only a small fraction of BglA is available to cellulosomes [43]. To address this problem,…”

“…Therefore, eliminating this feedback inhibition enables an enhanced biomass conversion [41]. The activity of β-glucosidase BglA was found to be too low in WT C. thermocellum strains [42], and due to the adsorption of cellulosomes in cellulose matrix, only a small fraction of BglA is available to cellulosomes [43]. To address this problem, Gefen et al (2012) [43] fused a β-glucosidase BglA protein with an unoccupied CohII and integrated this chimeric BglA-CohII complex into the purified C. thermocellum cellulosome.…”