Production of l-tagatose from galactitol by Klebsiella pneumoniae strain 40b

Ryu

et al. 2003

Biotechnology Progress

To develop a feasible enzymatic process for d-tagatose production, a thermostable l-arabinose isomerase, Gali152, was immobilized in alginate, and the galactose isomerization reaction conditions were optimized. The pH and temperature for the maximal galactose isomerization reaction were pH 8.0 and 65 degrees C in the immobilized enzyme system and pH 7.5 and 60 degrees C in the free enzyme system. The presence of manganese ion enhanced galactose isomerization to tagatose in both the free and immobilized enzyme systems. The immobilized enzyme was more stable than the free enzyme at the same pH and temperature. Under stable conditions of pH 8.0 and 60 degrees C, the immobilized enzyme produced 58 g/L of tagatose from 100 g/L galactose in 90 h by batch reaction, whereas the free enzyme produced 37 g/L tagatose due to its lower stability. A packed-bed bioreactor with immobilized Gali152 in alginate beads produced 50 g/L tagatose from 100 g/L galactose in 168 h, with a productivity of 13.3 (g of tagatose)/(L-reactor.h) in continuous mode. The bioreactor produced 230 g/L tagatose from 500 g/L galactose in continuous recycling mode, with a productivity of 9.6 g/(L.h) and a conversion yield of 46%.

Section: Introductionmentioning

confidence: 99%

A Feasible Enzymatic Process for d‐Tagatose Production by an Immobilized Thermostable l‐Arabinose Isomerase in a Packed‐Bed Bioreactor

Ryu

et al. 2003

Biotechnology Progress

Appl Microbiol Biotechnol

“…However, only two publications have focused on L-tagatose production from galactitol. Shimonishi et al used an isolated L-tagatose-producing bacterial strain from soil, Klebsiella pneumoniae strain 40b, to produce L-tagatose, with a yield of higher than 60 % from 0.5 to 2 % galactitol (Shimonishi et al 1995). Huwig et al developed a strategy for enzymatic production of Ltagatose from galactitol using a specific galactitol dehydrogenase from Rhodobacter sphaeroides D, with NADH regeneration by L-lactate dehydrogenase (EC 1.1.1.27) and with the overall yield of L-tagatose reaching 78 % (Huwig et al 1998).…”

Section: L-tagatose Production From Galactitolmentioning

confidence: 98%

Advances in the enzymatic production of l-hexoses

Chen

Zhang

et al. 2016

Rare sugars have recently drawn attention because of their potential applications and huge market demands in the food and pharmaceutical industries. All L-hexoses are considered rare sugars, as they rarely occur in nature and are thus very expensive. L-Hexoses are important components of biologically relevant compounds as well as being used as precursors for certain pharmaceutical drugs and thus play an important role in the pharmaceutical industry. Many general strategies have been established for the synthesis of L-hexoses; however, the only one used in the biotechnology industry is the Izumoring strategy. In hexose Izumoring, four entrances link the D- to L-enantiomers, ketose 3-epimerases catalyze the C-3 epimerization of L-ketohexoses, and aldose isomerases catalyze the specific bioconversion of L-ketohexoses and the corresponding L-aldohexoses. In this article, recent studies on the enzymatic production of various L-hexoses are reviewed based on the Izumoring strategy.

“…This is a compound of special interest on account of its use in the industrial production of vitamin C. The second system is L-tagatose production from D-galactitol (L-galactitol). Shimonishi et al (1995) reported upon its production using Klebsiella pneumoniae strain 40b, and Huwig et al (1998) also similarly reported it using galactitol dehydrogenase from Rhodobacter spaeroides. The third system is L-psicose production from D-allitol (L-allitol).…”

Section: Figmentioning

confidence: 99%

“…For the mass production of ketohexoses from hexitols, we could employ oxidoreductase reactions using microbial cells as catalysts, and sufficient amounts of rare ketohexoses were produced under aerobic conditions, D-tagatose from D-galactitol (Izumori et al 1984), and L-tagatose from D-galactitol (Shimonishi et al 1995). Using the reverse reactions of polyol dehydrogenases, various rare hexitols were prepared from ketohexoses by the action of microbe reactions, namely, D-talitol from D-tagatose (Muniruzzaman et al 1994); allitol from D-psicose (Muniruzzaman et al 1995); D-talitol from D-psicose (Sasahara et al 1998); and D-iditol from D-sorbose (Sasahara and Izumori 1999).…”

Section: Introductionmentioning

confidence: 99%

Bioproduction strategies for rare hexose sugars

Izumori

2002

Naturwissenschaften

Self Cite

193

110

A new strategy for the bioproduction of all ketohexoses was developed using hexitols as intermediates. Biocatalysts used to employ the strategy were D-tagatose 3-epimerase, which epimerizes ketohexoses at the C-3 position, and oxidoreductases, which catalyze oxidation-reduction reactions between ketohexoses and the corresponding hexitols. Arranging all the ketohexoses and hexitols in a symmetric ring and connecting them with 20 biochemical reactions, I was able to construct a design for the bioproduction of all the rare ketohexoses. Various aldose isomerases transform ketohexoses into the corresponding aldohexoses, so the strategy is useful for the bioproduction of all the rare hexose sugars. Furthermore, the design revealed that there are four routes to the L-hexose world from the D-hexose one.