A Thermostable phytase from <Emphasis Type="Italic">Neosartorya spinosa</Emphasis> BCC 41923 and its expression in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

A phytase gene was cloned from Neosartorya spinosa BCC 41923. The gene was 1,455 bp in size, and the mature protein contained a polypeptide of 439 amino acids. The deduced amino acid sequence contains the consensus motif (RHGXRXP) which is conserved among phytases and acid phosphatases. Five possible disulfide bonds and seven potential N-glycosylation sites have been predicted. The gene was expressed in Pichia pastoris KM71 as an extracellular enzyme. The purified enzyme had specific activity of 30.95 U/mg at 37°C and 38.62 U/mg at 42°C. Molecular weight of the deglycosylated recombinant phytase, determined by SDS-PAGE, was approximately 52 kDa. The optimum pH and temperature for activity were pH 5.5 and 50°C. The residual phytase activity remained over 80% of initial activity after the enzyme was stored in pH 3.0 to 7.0 for 1 h, and at 60% of initial activity after heating at 90°C for 20 min. The enzyme exhibited broad substrate specificity, with phytic acid as the most preferred substrate. Its K _m and V _max for sodium phytate were 1.39 mM and 434.78 U/mg, respectively. The enzyme was highly resistant to most metal ions tested, including Fe²⁺, Fe³⁺, and Al³⁺. When incubated with pepsin at a pepsin/phytase ratio of 0.02 (U/U) at 37°C for 2 h, 92% of its initial activity was retained. However, the enzyme was very sensitive to trypsin, as 5% of its initial activity was recovered after treating with trypsin at a trypsin/phytase ratio of 0.01 (U/U).     

Improved expression of a soluble single chain antibody fusion protein containing tumor necrosis factor in <Emphasis Type="Italic">Escherichia coli</Emphasis>

An epoxide hydrolase gene of about 0.8 kb was cloned from Rhodococcus opacus ML-0004, and the open reading frame (ORF) sequence predicted a protein of 253 amino acids with a molecular mass of about 28 kDa. An expression plasmid carrying the gene under the control of the tac promotor was introduced into Escherichia coli, and the epoxide hydrolase gene was successfully expressed in the recombinant strains. Some characteristics of purified recombinant epoxide hydrolase were also studied. Epoxide hydrolase showed a high stereospecificity for l(+)-tartaric acid, but not for d(+)-tartaric acid. The epoxide hydrolase activity could be assayed at the pH ranging from 3.5 to 10.0, and its maximum activity was obtained between pH 7.0 and 7.5. The enzyme was sensitive to heat, decreasing slowly between 30°C and 40°C, and significantly at 45°C. The enzyme activity was activated by Ca²⁺ and Fe²⁺, while strongly inhibited by Ag⁺ and Hg⁺, and slightly inhibited by Cu²⁺, Zn²⁺, Ba²⁺, Ni⁺, EDTA–Na₂ and fumarate.     

The ATPase activity of the <Emphasis Type="Italic">G2alt</Emphasis> gene encoding an aluminium tolerance protein from <Emphasis Type="Italic">Anoxybacillus gonensis</Emphasis> G2

The G2ALT gene was cloned and sequenced from the thermophilic bacterium Anoxybacillus gonensis G2. The gene is 666 bp long and encodes a protein 221 amino acids in length. The gene was overexpressed in E. coli and purified to homogeneity and biochemically characterized. The enzyme has a molecular mass of 24.5 kDa and it could be classified as a member of the family of bacterial aluminium resistance proteins based on homology searches. When this fragment was expressed in E. coli, it endowed E. coli with Al tolerance to 500 μM. The purified G2ALT protein is active at a broad pH range (pH 4.0–10.0) and temperature range (25°C–80°C) with optima of 6.0 and the apparent optimal temperature of 73°C respectively. Under optimal conditions, G2ALT exhibited a low ATPase activity with K _m ⁻ and V _max ⁻ values of 10±0.55 μM and 26.81±0.13 mg Pi released/min/mg enzyme, respectively. The ATPase activity of G2ALT requires Mg²⁺ and Na⁺ ions, while Zn²⁺ and Al³⁺ stimulate the activity. Cd²⁺ and Ag⁺ reduced the activity and Li⁺, Cu²⁺, and Co²⁺ inhibited the activity. Known inhibitors of most ATPases, like such as β-mercaptoethanol and ouabain, also inhibited the activity of the G2ALT. These biochemical characterizations suggested that G2ALT belongs to the PP-loop ATPase superfamily and it can be responsible for aluminium tolerance in A. gonensis G2.     

Cloning, expression, and characterization of a thermostable glucoamylase from Thermoanaerobacter tengcongensis MB4

A thermostable glucoamylase (TtcGA) from Thermoanaerobacter tengcongensis MB4 was successfully expressed in Escherichia coli. The full-length gene (2112 bp) encodes a 703-amino acid polypeptide including a predicted signal peptide of 21 residues. The recombinant mature protein was partially purified to 30-fold homogeneity by heat treatment and gel filtration chromatography. The mature protein is a monomer with the molecular weight of 77 kD. The recombinant enzyme showed maximum activity at 75 °C and pH 5.0. It is the most thermostable bacterial glucoamylase described to date with nearly no activity loss after incubation at 75 °C for 6 h. TtcGA can hydrolyze both α-1, 4- and α-1, 6-glycosidic linkages in various α-glucans. It showed preference for maltooligosaccharides over polysaccharides with specific activity of 80 U/mg towards maltose. Kinetic studies revealed that TtcGA had the highest activity on maltooligosaccharide with four monosaccharide units. The cations Ca²⁺, Mn²⁺, Co²⁺, Mg²⁺, and reducing agent DTT showed no obvious effects on the action of TtcGA. In contrast, the enzyme was inactivated by Zn²⁺, Pb²⁺, Cu²⁺, and EDTA.     

Cloning, purification, and characterization of a thermostable alpha-L-arabinofuranosidase from Anoxybacillus kestanbolensis AC26Sari

The gene, AbfAC26Sari, encoding an α-l-arabinofuranosidase from Anoxybacillus kestanbolensis AC26Sari, was isolated, cloned, sequenced, and characterizated. On the basis of amino acid sequence similarities, this 57-kDa enzyme could be assigned to family 51 of the glycosyl hydrolase classification system. Characterization of the purified recombinant α-l-arabinofuranosidase produced in Escherichia coli BL21 revealed that it is active at a broad pH range (pH 4.5 to 9.0) and at a broad temperature range (45–85°C) and it has an optimum pH of 5.5 and an optimum temperature of 65°C. Kinetic experiment at 65°C with p-nitrophenyl α-l-arabinofuranoside as a substrate gave a V _max and K _m values of 1,019 U/mg and 0.139 mM, respectively. The enzyme had no apparent requirement of metal ions for activity, and its activity was strongly inhibited by 1 mM Cu²⁺ and Hg²⁺. The recombinant arabinofuranosidase released l-arabinose from arabinan, arabinoxylan, oat spelt xylan, arabinobiose, arabinotriose, arabinotetraose, and arabinopentaose. Endoarabinanase activity was not detected. These findings suggest that AbfAC26Sari is an exo-acting enzyme.     

Cloning,Expression, Purification,and Characterization of Cold-Adapted α-Amylase from <Emphasis Type="Italic">Pseudoalteromonas arctica</Emphasis> GS230

A cold-adapted α-amylase (ParAmy) gene from Pseudoalteromonas arctica GS230 was cloned, sequenced, and expressed as an N-terminus His-tag fusion protein in E. coli. A recombinant protein was produced and purified with DEAE-sepherose ion exchange chromatography and Ni affinity chromatography. The molecular weight of ParAmy was estimated to be 55 KDa with sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). With an optimum temperature for activity 30 °C, ParAmy showed 34.5% of maximum activity at 0 °C and its activity decreased sharply at above 40 °C. ParAmy was stable in the range of pH 7–8.5 at 30 °C for 1 h. ParAmy was activated by Mn²⁺, K⁺ and Na⁺, and inhibited by Hg²⁺, Cu²⁺, and Fe³⁺. N-Bromosuccinimid showed a significant repressive effect on enzyme activity. The K _m and V _max values of the α-amylase for soluble starch were 7.28 mg/mL and 13.07 mg/mL min, respectively. This research suggests that Paramy has a good potential to be a cold-stable and alkalitolerant amylase in detergent industry.     

Expression,purification, and characterization of a novel acid phosphatase that displays protein tyrosine phosphatases activity from Metarhizium anisopliae strain CQMa102

The protein tyrosine phosphatase (PTPase) plays an important role in insect immune system. Our group has purified a type of acid phosphatase that could specifically dephosphorylate trans-Golgi p230 in vitro. In order to study this phosphatase further, we have identified and cloned the phosphatase gene from a locust specific Metarhizium anisopliae Strain CQMa102. The CQMa102 phosphatase was expressed in Pichia pastoris to verify its protease activity. The molecular weight (M_W) and the isoelectric point (pI) of the phosphatase were about 85 kDa and 6.15, respectively. Substrate specificity evaluation showed that the purified enzyme exhibited high activity on O-phospho-L-tyrosine. At its optimal pH of 6.5 and optimum temperature of 70 °C, the protein showed the highest activity respectively. It can be activated by Ca²⁺, Mg²⁺, Mn²⁺, Ba²⁺, Co²⁺ and phosphate analogs, but inhibited by Zn²⁺, Cu²⁺, fluoride, dithiothreitol, β-mercaptoethanol and N-ethylmaleimide.     

Characterization of hyperthermostable α-amylase from Geobacillus sp. IIPTN

A newly isolated Geobacillus sp. IIPTN (MTCC 5319) from the hot spring of Uttarakhand's Himalayan region produced a hyperthermostable α-amylase. The microorganism was characterized by biochemical tests and 16S rRNA gene sequencing. The optimal temperature and pH were 60°C and 6.5, respectively, for growth and enzyme production. Although it was able to grow in temperature ranges from 50 to 80°C and pH 5.5–8.5. Maximum enzyme production was in exponential phase with activity 135 U ml⁻¹ at 60°C. Assayed with cassava as substrate, the enzyme displayed optimal activity 192 U ml⁻¹ at pH 5.0 and 80°C. The enzyme was purified to homogeneity with purification fold 82 and specific activity 1,200 U mg⁻¹ protein. The molecular mass of the purified enzyme was 97 KDa. The values of K _m and V _max were 36 mg ml⁻¹ and 222 μmol mg⁻¹ protein min⁻¹, respectively. The amylase was stable over a broad range of temperature from 40°C to 120°C and pH ranges from 5 to 10. The enzyme was stimulated with Mn²⁺, whereas it was inhibited by Hg²⁺, Cu²⁺, Zn²⁺, Mg²⁺, and EDTA, suggesting that it is a metalloenzyme. Besides hyperthermostability, the novelty of this enzyme is resistance against protease.     

Isolation,purification, and characterization of haloalkaline xylanase from a marine <Emphasis Type="Italic">Bacillus pumilus</Emphasis> strain,GESF-1

A haloalkalitolerant xylanase-producing Bacillus pumilus strain, GESF1 was isolated from an experimental salt farm of CSMCRI. Birch wood xylan and xylose induced maximum xylanase production with considerable activity seen in wheat straw and no activity at all with caboxymethyl cellulose (CMC). A three step purification yielded 21.21-fold purification with a specific activity of 112.42 U/mg protein (unit expressed as μmole of xylose released per min). Xylanase produced showed an optimum activity at pH 8.0, with approximately 50 and 30% relative activity at a pH 6.0 and 10.0, respectively. The temperature optimum was 40°C and kinetic properties such as K_m and V_max were 5.3 mg/mL and 0.42 μmol/min/mL (6593.4 μmol/min/mg protein). Xylanase activity (160∼ 120%) was considerably enhanced in 2.5 to 7.5% NaCl with 87 and 73% retention of activity in 10 and 15% of NaCl. Enzyme activity was enhanced by Ca²⁺, Mn²⁺, Mg²⁺, and Na⁺ but strongly inhibited by heavy metals such as Hg²⁺, Fe³⁺, Cu²⁺, Cd²⁺, and Zn²⁺. Organic reagents such as β-Mercaptoethanol enhanced xylanase activity whereas EDTA strongly inhibited its activity. Xylanase, purified from the Bacillus pumilus strain, GESF1 could have potential biotechnological applications.     

Thermostable glucose-tolerant glucoamylase produced by the thermophilic fungus Scytalidium thermophilum

Glucoamylase produced byScytalidium thermophilum was purified 80-fold by DEAE-cellulose, ultrafiltration and CM-cellulose chromatography. The enzyme is a glycoprotein containing 9.8% saccharide, pI of 8.3 and molar mass of 75 kDa (SDS-PAGE) or 60 kDa (Sepharose 6B). Optima of pH and temperature with starch or maltose as substrates were 5.5/70 °C and 5.5/65 °C, respectively. The enzyme was stable for 1 h at 55 °C and for about 8 d at 4 °C, either at pH 7.0 or pH 5.5. Starch, amylopectin, glycogen, amylose and maltose were the substrates preferentially hydrolyzed. The activity was activated by 1 mmol/L Mg²⁺ (27%), Zn²⁺ (21%), Ba²⁺ (8%) and Mn²⁺ (5%).K _m and {ie11-1} values for starch and maltose were 0.21 g/L, 62 U/mg protein and 3.9 g/L, 9.0 U/mg protein, respectively. Glucoamylase activity was only slightly inhibited by glucose up to a 1 mol/L concentration.     

A thermoactive glucoamylase with biotechnological relevance from the thermoacidophilic Euryarchaeon <Emphasis Type="Italic">Thermoplasma acidophilum</Emphasis>

A gene encoding an intracellular glucoamylase was identified in the genome of the extreme thermoacidophilic Archaeon Thermoplasma acidophilum. The gene taGA, consisting of 1,911 bp, was cloned and successfully expressed in Escherichia coli. The recombinant protein was purified 22-fold to homogeneity using heat treatment, anion-exchange chromatography, and gel filtration. Detailed analysis shows that the glucoamylase, with a molecular weight of 66 kDa per subunit, is a homodimer in its active state. Amylolytic activity was measured over a wide range of temperature (40–90°C) and pH (pH 3.5–7) and was maximal at 75°C and at acidic condition (pH 5). The recombinant archaeal glucoamylase uses a variety of polysaccharides as substrate, including glycogen and amylose. Maximal activity was measured towards amylopectin with a specific activity of 4.2 U/mg and increased almost threefold in the presence of manganese. Calcium ions have a pronounced effect on enzyme stability; in the presence of 5 mM CaCl₂, the half-life increased from 15 min to 2 h at 80°C.     

Characterization of a recombinant thermostable xylanase from deep-sea thermophilic Geobacillus sp. MT-1 in East Pacific

A novel xylanase-producing thermophilic strain MT-1 was isolated from a deep-sea hydrothermal field in east Pacific. A xylanase gene encoding 331 amino-acid peptide from this isolate was cloned and expressed in Escherichia coli. The recombinant xylanase exhibited maximum activity at 70°C and had an optimum pH of 7.0. It was active up to 90°C and showed activity over a wide pH ranging from 5.5 to 10.0. The crude xylanase presented similar properties in temperature and pH to those of the recombinant xylanase. The recombinant xylanase was stable in 1 mM of enzyme inhibitors (PMSF, EDTA, 2-ME or DTT) and in 0.1% detergents (Tween 20, Chaps or Triton X-100), whereas, it was strongly inhibited by sodium dodecyl sulfate (SDS) (1 mM). In addition, its catalytic function was stable in the presence of Li⁺, Na⁺ or K⁺. However, it was strongly inhibited by Ni²⁺, Mn²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺ and Al³⁺ (1 or 0.1 mM). The K _m and V _max of the recombinant xylanase for oat spelt xylan were calculated to be 1.579 mg/ml and 289 μmol/(min • mg), respectively. Our study, therefore, presented a rapid overexpression and purification of xylanase from deep-sea thermophile aimed at improving the enzyme yield for industrial applications and scientific research.     

An L-arabinose isomerase from Acidothermus cellulolytics ATCC 43068: cloning, expression, purification, and characterization

The araA gene encoding an L-arabinose isomerase (L-AI) from the acido-thermophilic bacterium Acidothermus cellulolytics ATCC 43068 was cloned and overexpressed in Escherichia coli. The open reading frame of the L-AI consisted of 1,503 nucleotides encoding 501 amino acid residues. The recombinant L-AI was purified to homogeneity by heat treatment, ion-exchange chromatography, and gel filtration. The molecular mass of the enzyme was estimated to be approximately 55 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme was optimally active at 75°C and pH 7.5. It required divalent metal ions, either Mn²⁺ or Co²⁺, for both enzymatic activity and thermostability improvement at higher temperatures. The enzyme showed relatively high activity and stability at acidic pH. It exhibited over 90% of its maximal activity at pH 6.0 and retained 80% of activity after 12 h incubation at pH 6.0. Catalytic property study showed that the enzyme had an interesting catalytic efficiency. Its apparent K _m, V _max, and catalytic efficiency (k _cat/K _m) for D-galactose was 28.9 mM, 4.9 U/mg, and 9.3 mM⁻¹ min⁻¹, respectively. The enzyme carried out the isomerization of D-galactose to D-tagatose with a conversion yield over 50% after 12 h under optimal conditions, suggesting its potential in D-tagatose production.     

Cel8H,a novel endoglucanase from the halophilic bacterium <Emphasis Type="Italic">Halomonas</Emphasis> sp. S66-4: Molecular cloning,heterogonous expression,and biochemical characterization

A recombinant Escherichia coli clone expressing an endoglucanase was identified from a genomic library of the halophilic bacterium Halomonas sp. S66-4, and the enzyme was designated Cel8H. The cel8H gene consisted of 1,053 bp and encoded 350 amino acids sharing the highest identity of 48% to other known endoglucanases. The protein was expressed in E. coli BL21 (DE3) and purified to homogeneity. The purified recombinant enzyme had an optimal activity of 4.9 U/mg at pH 5 and 45°C toward the substrate carboxymethylcellulose. It exhibited extraordinary properties which differed from endoglucanases reported previously at the point of high salt tolerance above 5 M, simultaneously with high pH stability at pH 4–12 and high temperature stability at 40–60°C. Various substrate tests indicated that the enzyme hydrolyzes β-1,4-glucosidic bonds specifically.     

Production and partial purification of invertase using <Emphasis Type="Italic">Cympopogan caecius</Emphasis> leaf powder as substrate

The present study investigates the efficiency of Aspergillus niger to produce invertase, an industrially important enzyme by using powdered stem of Cympopogan caecius (Lemon grass) as sole substrate and sole carbon source for the microorganism. The molecular weight of invertase was estimated to be 66–70 kDa by sodium do decyl sulphate poly acrylamide gel electrophoresis (SDS PAGE). The production of the enzyme was studied at different pH scales ranging from pH 4.0 to 7.0 at a constant temperature of 30°C and 2% substrate concentration. The maximum production of invertase (specific activity −0.0516 μk/mg protein) was obtained at pH 5.5 at 30°C temperature, and incubation for 48 h. The activity was found to be stable at pH 5.5 for 30 min. The enzyme was found to be stable in the temperature range of 20–55°C. The effect of divalent metal ions Cu²⁺, Fe²⁺, Co²⁺ on the activity of the enzyme invertase showed that these ions affected the activity by a certain factor. The study can be further industrially exploited in a country-like India where lemon grass is found in plenty and can be used as substrate for enzyme production. Moreover, the preparation of the substrate is also a simple process.     

Expression, purification, and characterization of alanine racemase from Pseudomonas putida YZ-26

Alanine racemase catalyzes the interconversion of d- and l-alanine and plays an important role in supplying d-alanine, a component of peptidoglycan biosynthesis, to most bacteria. Alanine racemase exists mostly in prokaryotes and is generally absent in higher eukaryotes; this makes it an attractive target for the design of new antibacterial drugs. Here, we present the cloning and characterization of a new gene-encoding alanine racemase from Pseudomonas putida YZ-26. An open reading frame (ORF) of 1,230 bp, encoding a protein of 410 amino acids with a calculated molecular weight of 44,217.3 Da, was cloned into modified vector pET32M to form the recombinant plasmid pET–alr. After introduction into E.coli BL21, the strain pET-alr/E.coli BL21 expressed His₆-tagged alanine racemase. The recombinant alanine racemase was efficiently purified to homogeneity using Ni²⁺–NTA and a gel filtration column, with 82.5% activity recovery. The amino acid sequence deduced from the alanine racemase gene revealed identity similarities of 97.0, 93, 23, and 22.0% with from P. putida F1, P. putida200, P. aeruginosa, and Salmonella typhimurium, respectively. The recombinant alanine racemase is a monomeric protein with a molecular mass of 43 kDa. The enzyme exhibited activity with l-alanine and l-isoleucine, and showed higher specificity for the former compared with the latter. The enzyme was stable from pH 7.0–11.0; its optimum pH was at 9.0. The optimum temperature for the enzyme was 37°C, and its activity was rapidly lost at temperatures above 40°C. Divalent metals, including Sr²⁺, Mn²⁺, Co²⁺, and Ni²⁺ obviously enhanced enzymatic activity, while the Cu²⁺ ion showed inhibitory effects.     

Gene cloning, expression and characterization of an α-galactosidase from Pedobacter nyackensis MJ11 CGMCC 2503 with potential as an aquatic feed additive

A gene, aga-MJ11, encoding an α-galactosidase (EC 3.2.1.22) was cloned from Pedobacter nyackensis MJ11 CGMCC 2503, expressed in Escherichia coli, and biochemically characterized. The gene consisted of 2,163 nucleotides encoding a 720 amino acid–protein with a theoretical molecular weight of 82.6 kDa. The deduced amino acid sequence of Aga-MJ11 shared the highest identity of 51% to an α-galactosidase from Parabacteroides distasonis (YP_001301506), which belongs to glycoside hydrolase (GH) family 36. Purified recombinant Aga-MJ11-H showed optimal activity at pH 5.5 and 40°C, was stable at pH 4.0–10.0, retained ~80% of the maximum activity at 30°C (the optimum temperature for freshwater fish), exhibited tolerance to some proteases, and had a wide substrate specificity (pNPG, melidiose, stachyose and raffinose). All these features make Aga-MJ11 potentially useful for applications in aquaculture. The enzyme studied in the present work may represent a novel GH-36 α-galactosidase from the genus Pedobacter. X. Liu and K. Meng contributed equally to this work.     

Cloning,characterization and expression of the chitinase gene of <Emphasis Type="Italic">Enterobacter</Emphasis> sp. NRG4

A chitinase producing bacterium Enterobacter sp. NRG4, previously isolated in our laboratory, has been reported to have a wide range of applications such as anti-fungal activity, generation of fungal protoplasts and production of chitobiose and N-acetyl D-glucosamine from swollen chitin. In this paper, the gene coding for Enterobacter chitinase has been cloned and expressed in Escherichia coli BL21(DE3). The structural portion of the chitinase gene comprised of 1686 bp. The deduced amino acid sequence of chitinase has high degree of homology (99.0%) with chitinase from Serratia marcescens. The recombinant chitinase was purified to near homogeneity using His-Tag affinity chromatography. The purified recombinant chitinase had a specific activity of 2041.6 U mg⁻¹. It exhibited similar properties pH and temperature optima of 5.5 and 45°C respectively as that of native chitinase. Using swollen chitin as a substrate, the K_m, k_cat and catalytic efficiency (k_cat/K_m) values of recombinant chitinase were found to be 1.27 mg ml⁻¹, 0.69 s⁻¹ and 0.54 s⁻¹M⁻¹ respectively. Like native chitinase, the recombinant chitinase produced medicinally important N-acetyl D-glucosamine and chitobiose from swollen chitin and also inhibited the growth of many fungi.     

Cloning of a new endoglucanase gene from Bacillus sp. BP-23 and characterisation of the enzyme. Performance in paper manufacture from cereal straw

The gene celA, encoding an endoglucanase from the strain Bacillus sp. BP-23, was cloned and expressed in Escherichia coli. The nucleotide sequence of a 1867-bp DNA fragment containing the celA gene was determined, revealing an open reading frame of 1200 nucleotides that encodes a protein of 44 803 Da. The deduced amino acid sequence of the encoded enzyme shows high homology to those of enzymes belonging to subtype 4 of the family-A cellulases. The celA gene product synthesized in E. coli showed activity on carboxymethylcellulose and lichenan but no activity was found on Avicel. Activity was enhanced in the presence of 10 mM Mg²⁺ and Ca²⁺ and showed its maximum at 40 °C and pH 4.0. Study of the performance of CelA on paper manufacture from agricultural fibres showed that treatment with the enzyme improved the properties of the pulp and the quality of paper. CelA treatment enhanced the physical properties (stretch and tensile index) of paper from wheat straw, while dewatering properties were slightly diminished. Electron-microscope analysis showed that the surface of straw fibres was modified by CelA. Received: 11 February 1998 / Received revision: 20 March 1998 / Accepted: 20 March 1998