Characterization of a thermostable recombinant l‐rhamnose isomerase from Caldicellulosiruptor obsidiansis OB47 and its application for the production of l‐fructose and l‐rhamnulose

Abstract

The recombinant L-RI could effectively catalyze the formation of l-rhamnulose and l-fructose, suggesting that it was a promising candidate for industrial production of l-rhamnulose and l-fructose. © 2017 Society of Chemical Industry.

Food‐Grade Expression and Characterization of a Dextranase from Chaetomium gracile Suitable for Sugarcane Juice Clarification

“…The optimal temperature and pH using dextran T‐2000 as a substrate were at 55 °C and pH 5.0, respectively. In the present study, the recombinant DEX enzyme exhibited high activity under weak acidic conditions, which may decrease nonspecific reactions and the accumulation of undesirable byproducts that could be accrued under the alkaline conditions typically employed in the sugar industry [23] …”

“…In the present study, the recombinant DEX enzyme exhibited high activity under weak acidic conditions, which may decrease nonspecific reactions and the accumulation of undesirable byproducts that could be accrued under the alkaline conditions typically employed in the sugar industry. [23] Temperature stability is generally considered to be one of the primary factors determining whether an enzyme is suitable for industrial applications. [24] Herein, the recombinant enzyme retained 90.14, 88.27 and 71.36 % of initial activity after incubation at 40, 45 and 50°C for 60 min, respectively ( Figure 3C), but this decreased markedly following incubation above 55°C.…”

Improving Thermostability and Catalytic Behavior of l-Rhamnose Isomerase from Caldicellulosiruptor obsidiansis OB47 toward d-Allulose by Site-Directed Mutagenesis

“…The plasmid harboring the C. obsidiansis OB47 L-RI gene was constructed in our previous work. 27 The reagents used for sitedirected mutagenesis of wild-type L-RI gene were obtained from Generay Biotech Company, Ltd. Isopropyl-β-D-1-thiogalactopyranoside (IPTG) for induction was from Sigma. The Ni 2+ -chelating affinity-chromatography resin was provided by GE.…”

Characterization of Ribose-5-Phosphate Isomerase B from Newly Isolated Strain Ochrobactrum sp. CSL1 Producing L-Rhamnulose from L-Rhamnose

“…The biological production of L-rhamnulose by L-RhI from C. obsidiansis OB47 suggested that the different substrate concentrations exhibited influence on conversion. The higher concentration that led to lower conversion with time elapsing might be due to the product inhibition [4]. Aldose-ketose isomerization by the enzymatic method is reversible, and its reaction equilibrium is unfavorable for ketose formation [5].…”

“…L-Rhamnulose (6-deoxy-L-fructose), as one of the rare deoxy ketoses, is widely used in the food industry. As a starting material for preparing food flavors, it has been used widely because of its caramel-like aroma [4]. Moreover, it can be directly isomerized or epimerized into other rare sugars [5].…”