Degradation of rice bran hemicellulose by Paenibacillus sp. strain HC1: gene cloning, characterization and function of β-D-glucosidase as an enzyme involved in degradation

Abstract

A bacterium (strain HC1) capable of assimilating rice bran hemicellulose was isolated from a soil and identified as belonging to the genus Paenibacillus through taxonomical and 16S rDNA sequence analysis. Strain HC1 cells grown on rice bran hemicellulose as a sole carbon source inducibly produced extracellular xylanase and intracellular glycosidases such as beta-D-glucosidase and beta-D-arabinosidase. One of them, beta-D-glucosidase, was further analyzed. A genomic DNA library of the bacterium was constructed in Escherichia coli and gene coding for beta-D-glucosidase was cloned by screening for beta-D-glucoside-degrading phenotype in E. coli cells. Nucleotide sequence determination indicated that the gene for the enzyme contained an open reading frame consisting of 1,347 bp coding for a polypeptide with a molecular mass of 51.4 kDa. The polypeptide exhibits significant homology with other bacterial beta-D-glucosidases and belongs to glycoside hydrolase family 1. Beta-D-Glucosidase purified from E. coli cells was a monomeric enzyme with a molecular mass of 50 kDa most active at around pH 7.0 and 37 degrees C. Strain HC1 glycosidases responsible for degradation of rice bran hemicellulose are expected to be useful for structurally determining and molecularly modifying rice bran hemicellulose and its derivatives.

Purification of soluble rice bran fiber using ultrafiltration technology

“…Glucose, arabinose, xylose and galactose were found to be the main monomers in rice hemicelluloses (Bevenue & Williams, 1956;Carta no & Juliano, 1970;Gremli & Juliano, 1970). Rice bran hemicelluloses are reported to consist of xylan as a backbone and other sugars as side chains (Harada, Tanaka, Fukuda, Hashimoto, & Murata, 2005). The retained solutions of SRBF were concentrated hemicelluloses by the ultrafiltration process; therefore, the purified SRBF solution had greater levels of arabinose and xylose, but not galactose and glucose, than unpurified SRBF when they were hydrolyzed with sulfuric acid (Table 4).…”

Genome mining and motif modifications of glycoside hydrolase family 1 members encoded by Geobacillus kaustophilus HTA426 provide thermostable 6-phospho-β-glycosidase and β-fucosidase

“…β-Fucosidase activity was observed over a wide pH range (4.0-9.0) with an optimum pH 5.0-6.0. Although β-fucosidase activities have been reported for members of GH1 (Cairns et al 2000;Harada et al 2005;Kempton and Withers 1992;Marana et al 2001), GH5 (Yoshida et al 2011), and GH42 (Benešová et al 2010) families, and β-fucosidase activity has been purified from the latex serum of Lactuca sativa (Giordani and Noat 1988), an enzyme that Amino acid sequences of DG motifs from GK3214 (GenBank accession number, BAD77499), GK3214 mutants (NFE, MRF, and M8), GK1856 (BAD76141), and GK2337 (BAD7662) were compared with related sequences of 6-phospho-β-glycosidases (Witt et al 1993) from L. lactis (AAA25173), Lactobacillus casei (ACG55692), Staphylococcus aureus, E. coli (AAA23511) (Wilson and Fox 1974), and B. subtilis (BAA08975) (Setlow et al 2004) and of β-glycosidases from P. polymyxa (AAA22263) (Sanz-Aparicio et al 1998), Bifidobacterium breve (BAA19881) (Nunoura et al 1996), S. paucimobilis (AAG59862) (Marques et al 2003), P. furiosus (AAC25555 and AAC44387) (Bauer et al 1996), S. solfataricus (NP_344331) (Corbett et al 2001), Reticulitermes flavipes (ADK12988) (Scharf et al 2010), and Dalbergia cochinchinensis (AF163097) (Cairns et al 2000). Three highly conserved amino acids in DG motifs, aspartic acid (D), arginine (R), and glycine (G) residues, are indicated by solid triangles.…”

Characterization of a Thermostable Family 1 Glycosyl Hydrolase Enzyme from Putranjiva roxburghii Seeds

“…Enhancement of flavor through enzymatic hydrolysis of these glycosides has stimulated considerable research interest towards the natural aroma spectrum of wine, fruit juice and tea [17]. The β-glucosidase is an attractive source for enhancing nutritional value in different food products by converting isoflavone glycosides to their aglycones [18], biomass conversion [19] and ethanol production [20]. The β-galactosidases are known to hydrolyse lactose to glucose and galactose which can be widely used in food industry particularly in dairy industries for the production of lactose free or low lactose milk, production of probiotic foodstuff as galacto-oligosaccharide.…”