Enzymatic production of three 6-deoxy-aldohexoses from l-rhamnose

Abstract

6-Deoxy-l-glucose, 6-deoxy-l-altrose, and 6-deoxy-l-allose were produced from l-rhamnose with an immobilized enzyme that was partially purified (IE) and an immobilized Escherichia coli recombinant treated with toluene (TT). 6-Deoxy-l-psicose was produced from l-rhamnose by a combination of l-rhamnose isomerase (TT-PsLRhI) and d-tagatose 3-epimerase (TT-PcDTE). The purified 6-deoxy-l-psicose was isomerized to 6-deoxy-l-altrose and 6-deoxy-l-allose with l-arabinose isomerase (TT-EaLAI) and l-ribose isomerase (TT-AcLRI), respectively, and then was epimerized to l-rhamnulose with immobilized d-tagatose 3-epimerase (IE-PcDTE). Following purification, l-rhamnulose was converted to 6-deoxy-l-glucose with d-arabinose isomerase (TT-BpDAI). The equilibrium ratios of 6-deoxy-l-psicose:6-deoxy-l-altrose, 6-deoxy-l-psicose:6-deoxy-l-allose, and l-rhamnulose:6-deoxy-l-glucose were 60:40, 40:60, and 27:73, respectively. The production yields of 6-deoxy-l-glucose, 6-deoxy-l-altrose, and 6-deoxy-l-allose from l-rhamnose were 5.4, 14.6, and 25.1%, respectively. These results indicate that the aldose isomerases used in this study acted on 6-deoxy aldohexoses.

Novel process for producing 6-deoxy monosaccharides from l-fucose by coupling and sequential enzymatic method

“…The cultivation of 109-BpDAI and the expression of D-AI were conducted by a method previously described (16). KRX-PsLRhI was cultivated in LB medium supplemented with 100 mg/mL of ampicillin and incubated at 37 C with shaking at 250 rpm.…”

“…KRX-PsLRhI was cultivated in LB medium supplemented with 100 mg/mL of ampicillin and incubated at 37 C with shaking at 250 rpm. In contrast, KRX-AcLRI was cultivated in super broth (SB) medium (16) supplemented with 100 mg/mL of ampicillin and incubated at 30 C. After the cell cultures reached an OD 660 of 0.5e0.6, enzyme expression was induced by the addition of 1 mM IPTG. The cell cultures were incubated continuously at 25 C with shaking at 250 rpm for a total of 16e18 h.…”

“…Using a combination of chemical and enzymatic methods, all 12 of the 5-deoxyhexoses and 10 of the sixteen 1-and 6-deoxyketohexoses were produced in our laboratory (14,15). In addition, we recently reported that D-arabinose isomerase (D-AI), DTE, L-ribose isomerase (L-RI), and L-arabinose isomerase (L-AI) could act on 6-deoxy monosaccharides (16). These enzymes were applied to produce 6-deoxy-L-glucose, 6-deoxy-Lallose, and 6-deoxy-L-altrose from L-rhamnose via two intermediates, L-rhamnulose (6-deoxy-L-fructose) and 6-deoxy-Lallulose (16).…”

“…In addition, we recently reported that D-arabinose isomerase (D-AI), DTE, L-ribose isomerase (L-RI), and L-arabinose isomerase (L-AI) could act on 6-deoxy monosaccharides (16). These enzymes were applied to produce 6-deoxy-L-glucose, 6-deoxy-Lallose, and 6-deoxy-L-altrose from L-rhamnose via two intermediates, L-rhamnulose (6-deoxy-L-fructose) and 6-deoxy-Lallulose (16). Although allulose of 6-deoxy-L-allulose was previously called psicose, ISRS has recommended the use of the name allulose rather than psicose (Allulose-psicose nomenclature usage: http://isrs.kagawa-u.ac.jp/image/AlluloseNAME-2.pdf).…”

“…The current study and the previous report (16) are serial experiments under the main objectives of (i) to elucidate that microbial aldose isomerases and DTE-family enzyme, which their typical substrates are common monosaccharides, are able to catalyze the transformation of 6-deoxy monosaccharides, and (ii) to produce various 6-deoxy monosaccharides from commercially available substrate using combination of microbial enzymatic reactions. Here, we describe a methodology for producing four types of 6-deoxyhexoses: 6-deoxy-L-talose, 6-deoxy-L-sorbose, 6-deoxy-L-gulose, and 6-deoxy-L-idose.…”