Temperature management strategy for efficient gene expression in a thermally inducible <Emphasis Type="Italic">Escherichia coli</Emphasis>/bacteriophage system

In a two-phase operation, E. coli containing λSNNU1 (Q ⁻ S ⁻) in the chromosome is typically cultured at 33°C and cloned gene expression is induced by elevating the temperature. At least 40°C is necessary for complete induction of cloned gene expression; however, temperatures above 40°C have been shown to inhibit cloned gene expression. This suggests that a three-phase operation, which has an induction phase between the growth and production phases, may result in higher gene expression. In this study, optimal temperature management strategies were investigated for the three-phase operation of cloned gene expression in thermally inducible E. coli/bacteriophage systems. The optimal temperature for the induction phase was determined to be 40°C. When the temperature of the production stage was 33°C, the optimal time period for the induction phase at 40°C was determined to be 60 min. In contrast, when the temperature of the production phase was 37°C, the optimal period for the induction phase at 40°C was 20∼30 min. When the three-phase temperature and temporal profile were set at a growth phase of 33°C, an induction phase at 40°C for 30 min, and a production phase at 37°C, the highest level of cloned gene expression was achieved.     

Cryopreservation of <Emphasis Type="Italic">Dendrobium candidum</Emphasis> Wall. ex Lindl. protocorm-like bodies by encapsulation-vitrification

Protocorm-like bodies (PLBs) of Dendrobium candidum Wall. ex Lindl., orchid, were successfully cryopreserved using an encapsulation vitrification method. PLBs were precultured in liquid Murashige and Skoog (MS) medium containing 0.2 mg l⁻¹ α-naphthalene acetic acid and 0.5 mg l⁻¹ 6-benzyladenine enriched with 0.75 M sucrose, and grown under continuous light (36 μmol m⁻² s⁻¹) at 25 ± 1°C for 5 days. PLBs were osmoprotected with a mixture of 2 M glycerol and 1 M sucrose for 80 min at 25°C and dripped in a 0.5 M CaCl₂ solution containing 0.5 M sucrose at 25 ± 1°C and left for 15 min to form Ca-alginate beads (about 4 mm in diameter). Then, these were dehydrated with a plant vitrification solution 2 (PVS₂) consisting of 30% (w/v) glycerol, 15% (w/v) ethylene glycol, and 15% (w/v) dimethyl sulfoxide in 0.5 M sucrose, pH 5.8, for 150 min at 0°C. Encapsulated and dehydrated PLBs were plunged directly into liquid nitrogen for 1 h. Cryopreserved PLBs were then rapidly re-warmed in a water bath at 40°C for 3 min and then washed with MS medium containing 1.2 M sucrose for three times at 10 min intervals. Within 60 days, plantlets with the cryopreserved PLBs developed normal shoots and roots, and without any observed morphological abnormalities, were obtained. The survival rate of encapsulated-vitrified PLBs was above 85%. Thus, this encapsulation-vitrification method was deemed promising for cryopreservation of PLBs of D. candidum.     

Production of 3-hydroxypropionaldehyde using a two-step process with Lactobacillus reuteri

3-Hydroxypropionaldehyde (3-HPA) produced by Lactobacillus reuteri is a broad-spectrum antimicrobial substance of glycerol conversion. The aim of the present work was to optimize 3-HPA production by Lb. reuteri ATCC 53608 using a two-step process. The first step was the production of Lb. reuteri cells in optimal conditions. Cells were then harvested by centrifugation and suspended in glycerol solution, which the resting cells bioconverted to 3-HPA. The effect of biomass concentration, temperature, glycerol concentration, anaerobic/micro-aerophilic conditions, and incubation time was studied for high 3-HPA production. 3-HPA accumulation was limited by the death of cells in contact with high concentrations of 3-HPA. However, a very high 3-HPA concentration of 235±3 mM was obtained after 45 min of incubation at 30°C in 400 mM glycerol for an initial free-cell concentration of 1.6±0.3×10¹⁰ viable cells/ml. A high viability was maintained at low temperatures in the range 5–15°C, but with a slightly lower yield of 3-HPA at 5°C compared with higher temperatures, up to 37°C. Successive 1-h incubations of Lb. reuteri cells in 200 mM glycerol at 15°C to tentatively reuse the cells resulted in decreasing 3-HPA concentrations at the end of each cycle, with two successful production cycles yielding high 3-HPA concentrations of 147±1 mM and 128±2 mM.     

Effects of inoculum concentration,temperature, and carbon sources on tannase production during solid state fermentation of cashew apple bagasse

In this study, the optimization of tannase production by solid state fermentation was investigated using cashew apple bagasse (CAB), an inexpensive residue produced by the cashew apple agroindustry, as a substrate. To accomplish this, CAB was enriched with 2.5% (w/w) tannic acid and 2.5% (w/w) ammonium sulphate and then moistened with water (60 mL/100 g of dry CAB). The influence of inoculum concentration (10⁴ to 10⁷ spores/g), temperature (20, 25, 30, and 35°C) and several additional carbon sources (glucose, starch, sucrose, maltose, analytical grade glycerol, and glycerol produced during biodiesel production) on enzyme production by Aspergillus oryzae was then evaluated. Supplementation with maltose and glycerol inhibited tannase synthesis, which resulted in lower enzyme activity. Starch and sucrose supplementation increased enzyme production, but decreased the enzyme productivity. The maximum tannase activity (4.63 units/g of dry substrate) was obtained at 30°C, using 10⁷ spores/g and 1.0% (w/v) sucrose as an additional carbon source.     

Characterization of ribose-5-phosphate isomerase of <Emphasis Type="Italic">Clostridium thermocellum</Emphasis> producing <Emphasis Type="SmallCaps">d</Emphasis>-allose from <Emphasis Type="SmallCaps">d</Emphasis>-psicose

The rpiB gene, encoding ribose-5-phosphate isomerase (RpiB) from Clostridium thermocellum, was cloned and expressed in Escherichia coli. RpiB converted d-psicose into d-allose but it did not convert d-xylose, l-rhamnose, d-altrose or d-galactose. The production of d-allose by RpiB was maximal at pH 7.5 and 65°C for 30 min. The half-lives of the enzyme at 50°C and 65°C were 96 h and 4.7 h, respectively. Under stable conditions of pH 7.5 and 50°C, 165 g d-allose l⁻¹ was produced without by-products from 500 g d-psicose l⁻¹ after 6 h.     

Enhanced production of recombinant rabies virus glycoprotein (rRVGP) by Drosophila melanogaster S2 cells through control of culture conditions

Culture conditions that affect product quality are important to the successful operation and optimization of recombinant protein production. The objective of this study was to optimize culture conditions for growth of recombinant Drosophila melanogaster S2 cells (S2AcRVGP) in order to enhance the production of rRVGP. The addition of DMSO and glycerol to the medium and growth at a reduced temperature (22 °C) were the culture condition variations selected to be tested. Experimental cultures were first performed in serum-free Sf900 II medium in 250 ml Schott flasks. The most promising conditions identified in these experiments were also tested on a higher scale in a 3l bioreactor. In the Schott flasks experiments, all the changes in culture conditions resulted in an increase of rRVGP production. The protein concentration was 3.6-fold higher with addition of 1% DMSO and 1% glycerol and 9.3-fold higher when the cells were cultured at 22 °C instead of the standard 28 °C. The maximum concentration of rRVGP reached was 591 μg l⁻¹. In bioreactor experiments, with control of pH at 6.20 and DO at 50%, the reduced culture temperature (22 °C) was the strategy that promoted the highest glycoprotein production, 928 μg l⁻¹.     

<Emphasis Type="Bold">Characterization of nitrile hydratation catalysed by </Emphasis><Emphasis Type="BoldItalic">Nocardia</Emphasis><Emphasis Type="Bold"> sp. 108</Emphasis>

Abstract Nocardia sp. 108 exhibited strong acrylonitrile-hydrating activity and its nitrile hydratase was Co²⁺-dependent. Nocardia sp. 108 was active within a broad pH range from 6.0 to 10.0 at 30°C and thermostable at temperatures below 35°C, but became unstable at temperatures above 45°C. Furthermore, it was found that Nocardia sp. 108 can hydrate indole-3-acetonitrile, p-chlorobenzonitrile, p-hydroxybenzylcyanide, 3,4,5-trimethoxybenzonitrile, p-aminobenzonitrile, 3-cyanopyridine, o-chlorobenzonitrile to the corresponding amides and hence displayed a broad substrate specificity. The temperature and pH optima for these hydrations were 28°C and pH 7.0–7.5, respectively. At the observed concentrations, acrylonitrile was completely converted within 5 min, while 3,4,5-trimethoxybenzonitrile, p-aminobenzonitrile, indole-3-acetonitrile, p-chlorobenzonitrile were approximately 21.71, 8.98, 34.44, 93.10% hydrated. p-Chlorobenzonitrile appeared to be the preferred aromatic nitrile for Nocardia sp. 108.     

<Emphasis Type="Italic">Thermotoga maritima</Emphasis> TM0298 is a highly thermostable mannitol dehydrogenase

Thermotoga maritima TM0298 is annotated as an alcohol dehydrogenase, yet it shows high identity and similarity to mesophilic mannitol dehydrogenases. To investigate this enzyme further, its gene was cloned and expressed in Escherichia coli. The purified recombinant enzyme was most active on fructose and mannitol, making it the first known hyperthermophilic mannitol dehydrogenase. T. maritima mannitol dehydrogenase (TmMtDH) is optimally active between 90 and 100 °C and retains 63% of its activity at 120 °C but shows no detectable activity at room temperature. Its kinetic inactivation follows a first-order mechanism, with half-lives of 57 min at 80 °C and 6 min at 95 °C. Although TmMtDH has a higher V _max with NADPH than with NADH, its catalytic efficiency is 2.2 times higher with NADH than with NADPH and 33 times higher with NAD⁺ than with NADP⁺. This cofactor specificity can be explained by the high density of negatively charged residues (Glu193, Asp195, and Glu196) downstream of the NAD(P) interaction site, the glycine motif. We demonstrate that TmMtDH contains a single catalytic zinc per subunit. Finally, we provide the first proof of concept that mannitol can be produced directly from glucose in a two-step enzymatic process, using a Thermotoga neapolitana xylose isomerase mutant and TmMtDH at 60 °C.     

Effect of temperature on <Emphasis Type="SmallCaps">d</Emphasis>-arabitol production from lactose by <Emphasis Type="Italic">Kluyveromyces lactis</Emphasis>

d-Arabitol production from lactose by Kluyveromyces lactis NBRC 1903 has been studied by following the time courses of concentrations of cell mass, lactose, d-arabitol, ethanol, and glycerol at different temperatures. It was found that temperature is a key factor in d-arabitol production. Within temperatures ranging from 25 to 39°C, the highest d-arabitol concentration of 99.2 mmol l⁻¹ was obtained from 555 mmol l⁻¹ of lactose after 120 h of batch cultivation at 37°C. The yield of d-arabitol production on cell mass growth increased drastically at temperatures higher than 35°C, and the yield reached 1.07 at 39°C. Increasing the cell mass concentration two-fold after 24 h of culture growth at 37°C, the d-arabitol concentration further increased to 168 mmol l⁻¹. According to the distribution of the metabolic products, metabolic changes related to growth phase were also discussed. The stationary-phase K. lactis cells in the batch culture that is started with exposing the precultured inoculum to high osmotic stress, high oxidative stress, and high heat stress are found to be preferable for d-arabitol production.     

High-efficiency vitrification protocols for cryopreservation of in vitro grown shoot tips of rare and endangered plant <Emphasis Type="Italic">Emmenopterys henryi</Emphasis> Oliv.

In vitro-grown shoot tips of Emmenopterys henryi Oliv. were successfully cryopreserved by vitrification. Shoot tips excised from 3-month old plantlets were precultured in a liquid hormone-free Murashige and Skoog (MS) medium supplemented with 0.5 M sucrose for 3 days at 25°C and then treated with a mixture of 2 M glycerol plus 0.4 M sucrose (LS solution) for 40 min at 25°C. Osmo-protected shoot tips were first dehydrated with 60% vitrification solution (PVS₂) for 30 min at 0°C and followed by 100% PVS₂ for 40 min at 0°C. After changing the solution with fresh 100% PVS₂, the shoot tips were directly plunged into liquid nitrogen. After rapid warming in a water-bath at 40°C for 2 min, the shoot tips were washed for 20 min at 25°C with liquid MS medium containing 1.2 M sucrose and then transferred onto solid MS medium supplemented with kinetin 2 mg l⁻¹, α-naphthaleneacetic acid 0.1 mg l⁻¹, 3% (w/v) sucrose and 0.75% (w/v) agar. The shoot tips were kept in the dark for 7 days prior to exposure to the light (12 h photoperiod cycle). Direct shoot elongation was observed in approximately 12 days. The regeneration rate was approximately 75–85%. This method appears to be a promising technique for cryopreserving shoot tips of Emmenopterys henryi Oliv. germplasm.     

Production and characterization of thermostable alkaline phytase from <Emphasis Type="Italic">Bacillus laevolacticus</Emphasis> isolated from rhizosphere soil

A novel phytase producing thermophilic strain of Bacillus laevolacticus insensitive to inorganic phosphate was isolated from the rhizosphere soil of leguminous plant methi (Medicago falacata). The culture conditions for production of phytase by B. laevolacticus under shake flask culture were optimized to obtain high levels of phytase (2.957 ± 0.002 U/ml). The partially purified phytase from B. laevolacticus strain was optimally active at 70 °C and between pH 7.0 and pH 8.0. The enzyme exhibited thermostability with ∼80% activity at 70 °C and pH 8.0 for up to 3 h in the presence/absence of 5 mM CaCl₂. The phytase from B. laevolacticus showed high specificity for phytate salts of Ca⁺ > Na⁺. The enzyme showed an apparent K _m 0.526 mM and V _max 12.3 μmole/min/mg of activity against sodium phytate.     

Production of xylanase from a newly isolated <Emphasis Type="Italic">Penicillium</Emphasis> sp. ZH-30

A new strain of Penicillium sp. ZH-30 that produces xylanase was isolated from soil. According to the morphology and comparison of internal transcribed spacer (ITS) rDNA gene sequence, the strain Penicillium sp. ZH-30 was identified as a strain of Penicillium oxalicum. When xylan or wheat bran was used as substrate at 30°C for 3 days under submerged cultivation, xylanase production was 5.3 and 13.3 U ml⁻¹, respectively. The temperature and pH for optimum activity were 50°C and 5.0–6.0, respectively.     

Effects of circadian rhythms of fluctuating temperature on growth and biochemical composition of <Emphasis Type="Italic">Ulva pertusa</Emphasis>

The marcoalga Ulva pertusa was cultured under (20 ± 2)°C, (20 ± 4)°C, (20 ± 6)°C, (20 ± 8)°C and (20 ± 10)°C circadian rhythms of fluctuating temperature conditions, and constant temperature of 20°C was used as the control. The growth rate of macroalga at (20 ± 2)°C, (20 ± 4)°C and (20 ± 6)°C were significantly higher than that at constant temperature of 20°C, while growth rate at (20 ± 8)°C and (20 ± 10)°C were significantly lower than that at constant temperature of 20°C. The growth rate of macroalga was a quadratic function of the thermal amplitude. Such a growth model can be described by G = β ₀ + β ₁(TA) + β ₂(TA)², where G represents the relative growth rate, TA is thermal amplitude in degree Celsius, β ₀ is the intercept on the G axis, and β ₁ and β ₂ are the regression coefficients. The optimal thermal amplitude for the growth of thallus at mean temperature of 20°C was estimated to be ± 3.69°C. Analysis of biochemical composition at the final stages of thaulls growth revealed that diel fluctuating temperature caused various influences (P < 0.05). The content of chlorophyll, protein and total solute carbohydrate at (20 ± 2)°C and (20 ± 4)°C were slightly higher than those at constant temperature of 20°C, however no statistically significant differences were found among them (P > 0.05). While osmolytes (total solute carbohydrate and free proline) at (20 ± 10)°C were significantly higher than that at 20°C (P < 0.05). Therefore, more chlorophyll and carbohydrate production might account for the enhancement in the growth of macroalga at the diel fluctuating temperatures in the present study. Handling editor: S. M. Thomaz     

Enzymatic resolution of racemic phenyloxirane by a novel epoxide hydrolase from Aspergillus niger SQ-6 and its fed-batch fermentation

A microorganism with the ability to catalyze the resolution of racemic phenyloxirane was isolated and identified as Aspergillus niger SQ-6. Chiral capillary electrophoresis was successfully applied to separate both phenyloxirane and phenylethanediol. The epoxide hydrolase (EH) involved in this resolution process was (R)-stereospecific and constitutively expressed. When whole cells were used during the biotransformation process, the optimum temperature and pH for stereospecific vicinal diol production were 35°C and 7.0, respectively. After a 24-h conversion, the enantiomer excess of (R)-phenylethanediol produced was found to be >99%, with a conversion rate of 56%. In fed-batch fermentations at 30°C for 44 h, glycerol (20 g L⁻¹) and corn steep liquor (CSL) (30 g L⁻¹) were chosen as the best initial carbon and nitrogen sources, and EH production was markedly improved by pulsed feeding of sucrose (2 g L⁻¹ h⁻¹) and continuous feeding of CSL (1 g L⁻¹ h⁻¹) at a fermentation time of 28 h. After optimization, the maximum dry cell weight achieved was 24.5±0.8 g L⁻¹; maximum EH production was 351.2±13.1 U L⁻¹ with a specific activity of 14.3±0.5 U g⁻¹. Partially purified EH exhibited a temperature optimum at 37°C and pH optimum at 7.5 in 0.1 M phosphate buffer. This study presents the first evidence for the existence of a predicted epoxide racemase, which might be important in the synthesis of epoxide intermediates.     

Extracellular lipase of <Emphasis Type="Italic">Aspergillus niger</Emphasis> NRRL3; production,partial purification and properties

Four strains of Aspergillus niger were screened for lipase production. Each was cultivated on four different media differing in their contents of mineral components and sources of carbon and nitrogen. Aspergillus niger NRRL3 produced maximal activity (325U/ml) when grown in 3% peptone, 0.05% MgSO₄.7H₂O, 0.05% KCl, 0.2% K₂HPO₄ and 1% olive oil:glucose (0.5:0.5). A. niger NRRL3 lipase was partially purified by ammonium sulphate precipitation. The majority of lipase activity (48%) was located in fraction IV precipitated at 50–60% of saturation with a 18-fold enzyme purification. The optimal pH of the partial purified lipase preparation for the hydrolysis of emulsified olive oil was 7.2 and the optimum temperature was 60°C. At 70°C, the enzyme retained more than 90% of its activity. Enzyme activity was inhibited by Hg²⁺ and K⁺, whereas Ca²⁺ and Mn²⁺ greatly stimulated its activity. Additionally, the formed lipase was stored for one month without any loss in the activity.     

CITRIC ACID PRODUCTION BY Candida SPECIES GROWN ON A SOY-BASED CRUDE GLYCEROL

Citric acid was produced by five species of the yeast Candida after growth on a medium containing soy biodiesel-based crude glycerol. After growth on a medium containing 10 g L^?1 or 60 g L^?1 crude glycerol for 168 hr at 30°C, Candida parapsilosis ATCC 7330 and C. guilliermondii ATCC 9058 produced the highest citric acid levels. On 10 g L^?1 or 60 g L^?1 crude glycerol for 168 hr at 30°C, the citric acid level produced by C. parapsilosis ATCC 7330 was 1.8 g L^?1 or 11.3 g L^?1, respectively, while C. guilliermondii ATCC 9058 produced citric acid concentrations of 3.0 g L^?1 or 10.4 g L^?1, respectively. Biomass production by C. guilliermondii ATCC 9058 on 10 g L^?1 or 60 g L^?1 crude glycerol for 168 hr at 30°C was highest at 1.2 g L^?1 or 6.9 g L^?1, respectively. The citric acid yields observed for C. guilliermondii ATCC 9058 after growth on 10 g L^?1 or 60 g L^?1 crude glycerol (0.35 g g^?1 or 0.21 g g^?1, respectively) were generally higher than for the other Candida species tested. When similar crude glycerol concentrations were present in the culture medium, citric acid yields observed for some of the Candida species utilized in this study were about the same or higher compared to citric acid yields by Yarrowia lipolytica strains. Based on the findings, it appeared that C. guilliermondii ATCC 9058 was the most effective species utilized, with its citric acid production being similar to what has been observed when citric acid-producing strains of Y. lipolytica were grown on crude glycerol under batch conditions that could be of significance to biobased citric acid production.     

Cryopreservation of chestnut by vitrification of <Emphasis Type="Italic">in vitro</Emphasis>-grown shoot tips

Summary Plants of European chestnut (Castanea sativa) have been consistently recovered from cryopreserved in vitro-grown shoot apices by using the vitrification procedure. Factors found to influence the success of cryopreservation include the source of the shoot tips (terminal buds or axillary buds), their size, the duration of exposure to the cryoprotectant solution, and the composition of the post-cryostorage recovery medium. The most efficient protocol for shoot regrowth employed 0.5–1.0 mm shoot tips isolated from 1 cm-long terminal buds that had been excised from 3–5-wk shoot cultures and cold hardened at 4°C for 2 wk. The isolated shoot tips were precultured for 2d at 4°C on solidified Gresshoff and Doy medium (GD) supplemented with 0.2M sucrose, and were then treated for 20 min at room temperature with a loading solution (2M glycerol+0.4M sucrose) and for 120 min at 0°C with a modified PVS2 solution before rapid immersion in liquid nitrogen (LN). After 1 d in LN, rapid rewarming and unloading in 1.2M sucrose solution for 20 min, the shoot tips were plated on recovery medium consisting of GD supplemented with 2.2 μM benzyladenine, 2.9 μM 3-indoleacetic acid, and 0.9 μM zeatin. This protocol achieved 38–54% shoot recovery rates among five chestnut clones (three of juvenile origin and two of mature origin), and in all cases plant regeneration was also obtained.     

Optimal activity and thermostability of xylose reductase from <Emphasis Type="Italic">Debaryomyces hansenii</Emphasis> UFV-170

Xylose reductase (XR) is the enzyme that catalyzes the first step of xylose metabolism. Although XRs from various yeasts have been characterized, little is known about this enzyme in Debaryomyces hansenii. In the present study, response surface analysis was used to determine the optimal conditions for D. hansenii UFV-170 XR activity. The influence of pH and temperature, ranging from 4.0 to 8.0 and from 25 to 55°C, respectively, was evaluated by a 2² central composite design face-centered. The F-test (ANOVA) and the Student’s t test were performed to evaluate the statistical significance of the model and the regression coefficients, respectively. The NADPH-dependent XR activity varied from 0.502 to 2.53 U mL⁻¹, corresponding to 0.07–0.352 U mg⁻¹, whereas the NADH-dependent one was almost negligible. The model predicted with satisfactory correlation (R ² = 0.940) maximum volumetric activity of 2.27 U mL⁻¹ and specific activity of 0.300 U mg⁻¹ at pH 5.3 and 39°C, which were fairly confirmed by additional tests performed under these conditions. The enzyme proved very stable at low temperature (4°C), keeping its activity almost entirely after 360 min, which corresponded to the half-time at 39°C. On the other hand, at temperatures ≥50°C it was lost almost completely after only 20 min.     

Optimization of culture conditions for 1,3-propanediol production from crude glycerol by <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> using response surface methodology

To produce 1,3-propanediol (1,3-PD) from crude glycerol, cultivation conditions were optimized by response surface methodology (RSM) based on a 2⁵ factorial central composite design (CCD). RSM was adopted to derive a statistical model for the individual and interactive effects of crude glycerol, (NH₄)₂SO₄, pH, cultivation time and temperature on the production of 1,3-PD. Optimal conditions for maximum 1,3-PD production were as follows: crude glycerol, 35 g/L; (NH₄)₂SO₄, 8 g/L; pH, 7.37; cultivation time, 10.8 h; temperature, 36.88°C. Under these optimal conditions, the design expert presented the maximal numerical solution with a predicted 1,3-PD production level of up to 13.74 g/L. The experimental production of 1,3-PD yielded 13.8 g/L, which was in close agreement with the model prediction.     

A cold-active and thermostable alcohol dehydrogenase of a psychrotorelant from Antarctic seawater, <Emphasis Type="Italic">Flavobacterium frigidimaris</Emphasis> KUC-1

An NAD⁺-dependent alcohol dehydrogenase of a psychrotorelant from Antarctic seawater, Flavobacterium frigidimaris KUC-1 was purified to homogeneity with an overall yield of about 20% and characterized enzymologically. The enzyme has an apparent molecular weight of 160k and consists of four identical subunits with a molecular weight of 40k. The pI value of the enzyme and its optimum pH for the oxidation reaction were determined to be 6.7 and 7.0, respectively. The enzyme contains 2 gram-atoms Zn per subunit. The enzyme exclusively requires NAD⁺ as a coenzyme and shows the pro-R stereospecificity for hydrogen transfer at the C4 position of the nicotinamide moiety of NAD⁺. F. frigidimaris KUC-1 alcohol dehydrogenase shows as high thermal stability as the enzymes from thermophilic microorganisms. The enzyme is active at 0 to over 85°C and the most active at 70°C. The half-life time and k _cat value at 60°C were calculated to be 50 min and 27,400 min⁻¹, respectively. The enzyme also shows high catalytic efficiency at low temperatures (0–20°C) (k _cat/K _m at 10°C; 12,600 mM⁻¹ min⁻¹) similar to other cold-active enzymes from psychrophiles. The alcohol dehydrogenase gene is composed of 1,035 bp and codes 344 amino acid residues with an estimated molecular weight of 36,823. The sequence identities were found with the amino acid sequences of alcohol dehydrogenases from Moraxella sp. TAE123 (67%), Pseudomonas aeruginosa (65%) and Geobacillus stearothermophilus LLD-R (56%). This is the first example of a cold-active and thermostable alcohol dehydrogenase.