Direct ethanol production from N-acetylglucosamine and chitin substrates by Mucor species

Chitin, which is a polymer of β-(1–4) linked N-acetyl-d-glucosamine (GlcNAc) residues, is one of the most abundant renewable resources in nature, after cellulose. In this study, we found some native Mucor strains, which can use GlcNAc and chitin substrates as carbon sources for growth and ethanol production. One of these strains, M. circinelloides NBRC 6746 produced 18.6 ± 0.6 g/l of ethanol from 50 g/l of GlcNAc after 72 h and the maximum ethanol production rate was 0.75 ± 0.1 g/l/h. Furthermore, M. circinelloides NBRC 4572 produced 6.00 ± 0.22 and 0.46 ± 0.04 g/l of ethanol from 50 g/l of colloidal chitin and chitin powder after 16 and 12 days, respectively. We also found an extracellular chitinolytic enzyme producing strain M. ambiguus NBRC 8092, and successfully improved ethanol productivity of NBRC 4572 from colloidal chitin using crude chitinolytic enzyme derived from NBRC 8092. The ethanol titer reached 9.44 ± 0.10 g/l after 16 days. These results were the first bioethanol production from GlcNAc and chitin substrates by native organisms, and also suggest that these Mucor strains have great potential for the simultaneous saccharification and fermentation (SSF) of chitin biomass.     

Physicochemical characterization of chitin and chitosan from crab shells

Crab chitosan was prepared by alkaline N-deacetylation of crab chitin for 60, 90 and 120 min and the yields were 30.0-32.2% with that of chitosan C120 being the highest. The degree of N-deacetylation of chitosans (83.3–93.3%) increased but the average molecular weight (483–526 kDa) decreased with the prolonged reaction time. Crab chitosans showed lower lightness and WI values than purified chitin, chitosans CC and CS but higher than crude chitin. With the prolonged reaction time, the nitrogen (8.9–9.5%), carbon (42.2–45.2%) and hydrogen contents (7.9–8.6%) in chitosans prepared consistently increased whereas N/C ratios remained the same (0.21). Crab chitosans prepared showed a melting endothermic peak at 152.3–159.2 °C. Three chitosans showed similar microfibrillar crystalline structure and two crystalline reflections at 2θ = 8.8–9.0° and 18.9–19.1°. Overall, the characteristics of three crab chitosans were unique and differed from those of chitosan CC and CS as evidenced by the element analysis, differential scanning calorimetry, scanning electron microscopy and X-ray diffraction patterns.     

Immunotherapeutic effects of chitin in comparison with chitosan against Leishmania major infection

Chitin and chitosan microparticles (MPs) are important immune system stimulators. The aim of this study was to evaluate the protective effects of these compounds in comparison with each other against Leishmania infection in BALB/c mice infected with Leishmania major (L. major).Female BALB/c mice were injected subcutaneously with 2 × 10⁵ promastigotes. Chitin and/or chitosan MPs (< 40 μm) were subcutaneously injected in the BALB/c mice with two-day intervals until two weeks. Mice in all groups were sacrificed at 12 weeks post-infection. Enumeration of viable parasites was performed using limiting dilution assay. Furthermore, the animals (5 mice/group) were sacrificed two weeks post-infection. The lymph node cells were isolated and the effects of the chitinous MPs on the proliferation and production of cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) were determined. The mean sizes of lesions were significantly smaller in chitin (0.6 ± 0.12 mm) and chitosan treated groups (1.2 ± 0.8 mm) than in the control group (6.2 ± 1.7 mm) (P < 0.05). The parasite load in the lymph nodes of the treated mice was significantly lower than that in the lymph nodes of controls (1.31 × 10⁶ vs 8.24 × 10⁷ parasite/lymph node [P = 0.032] and 7.49 × 10⁶ vs 8.24 × 10⁷ parasite/lymph node [P = 0.05] for chitin and chitosan MPs treatment, respectively). We found that chitinous MPs induced cell proliferation and that chitin but not chitosan increased TNF-α and IL-10 production. Chitin appears that it has more effect than chitosan against leishmaniasis. The current study revealed that chitinous MPs had significant activity against L. major and could be considered as new therapeutic modality in leishmaniasis.     

Comparative biochemical characterization of soluble and chitosan immobilized β-galactosidase from Kluyveromyces lactis NRRL Y1564

An investigation was conducted on the production of β-galactosidase (β-gal) by different strains of Kluyveromyces, using lactose as a carbon source. The maximum enzymatic activity of 3.8 ± 0.2 U/mL was achieved by using Kluyveromyces lactis strain NRRL Y1564 after 28 h of fermentation at 180 rpm and 30 °C. β-gal was then immobilized onto chitosan and characterized based on its optimal operation pH and temperature, its thermal stability and its kinetic parameters (K_m and V_max) using o-nitrophenyl β-d-galactopyranoside as substrate. The optimal pH for soluble β-gal activity was found to be 6.5 while the optimal pH for immobilized β-gal activity was found to be 7.0, while the optimal operating temperatures were 50 °C and 37 °C, respectively. At 50 °C, the immobilized enzyme showed an increased thermal stability, being 8 times more stable than the soluble enzyme. The immobilized enzyme was reused for 10 cycles, showing stability since it retained more than 70% of its initial activity. The immobilized enzyme retained 100% of its initial activity when it was stored at 4 °C and pH 7.0 for 93 days. The soluble β-gal lost 9.4% of its initial activity when it was stored at the same conditions.     

Milk-clotting enzymes produced by culture of Bacillus subtilis natto

Factors affecting the production of milk-clotting enzyme (MCE) by Bacillus subtilis (natto) Takahashi, a ready available commercial natto starter, were studied. Remarkable milk-clotting activity (MCA), 685.7 SU/ml or 12,000 SU/g, was obtained when the bacteria were cultivated in the medium containing sucrose (50 g/L) and basal salts at pH 6, 37 °C with shaking at 175 rpm for 1 day. The MCA and MCA/PA ratio of the crude enzyme obtained are comparable with those of Pfizer microbial rennin and Mucor rennin. The crude enzyme showed excellent pH and thermal stability; it retained 96% of MCA after incubation for 40 min at 40 °C and retained more than 80% of its activity between pH 4 and pH 7 for more than 30 min at 30 °C. The MCE of B. subtilis (natto) Takahashi has potential as calf rennet substitutes.     

Glucoamylase production by the marine yeast Aureobasidium pullulans N13d and hydrolysis of potato starch granules by the enzyme

Under the optimal conditions, 10 U/ml of glucoamylase was produced by the marine yeast Aureobasidium pullulans N13d. It was noticed that the crude glucoamylase actively hydrolyzed potato starch granules, but poorly digested raw corn starch and sweet potato starch, resulting in conversion of 68.5, 19 and 22% of them into glucose within 6 h of incubation in the presence of 40 g/l of potato starch granules and 20 U/ml of the crude enzyme. When potato starch granules concentration was increased from 10 to 80 g/l, hydrolysis extent was decreased from 85.6 to 60%, while potato starch granules concentration was increased from 80 to 360 g/l, hydrolysis extent was decreased from 60 to 56%. Ratio of hydrolysis extent of potato starch granules to hydrolysis extent of gelatinized potato starch was 86.0% and the hydrolysis extent of potato starch granules by action of the crude glucoamylase (1.0 U/ml) was 18.5% within 30 min at 60 °C. Only glucose was detected during the hydrolysis, indicating that the crude enzyme could hydrolyze both α-1,4 and α-1,6 linkages of starch molecule in the potato starch.     

Recovery of protein,chitin, carotenoids and glycosaminoglycans from Pacific white shrimp (Litopenaeus vannamei) processing waste

Shrimp head waste is a major byproduct of crustacean processing in North-eastern Brazil and represents an interesting source of bioactive molecules. Additionally, its use increases the sustainability of processing fishery products. The present study reports a process developed for recovering bioactive molecules from shrimp heads through autolysis. A protein hydrolysate (120 ± 0.4 g) formed by a 9% (w/v) solution was recovered and lyophilized from 1 kg of shrimp heads. Approximately 195 ± 0.5 mg of carotenoids was recovered as an ethanolic extract. The recovery of chitin and chitosan were 25 ± 2 g kg^?1 and 17 ± 4 g kg^?1 wet processing waste, respectively. Chitosans were characterized by ¹³C NMR, and FT-IR analysis and exhibited a variable degree of deacetylation (60–80%). Sulfated glycosaminoglycans that exhibited electrophoretic migration similar to mammalian standards were also recovered (79 ± 2 mg kg^?1 wet processing waste), and their degradation products suggested the presence of C6-sulfated heparan sulfate. These data point to the feasibility of an integrated process for isolating highly bioactive molecules, such as sulfated- and amino-polysaccharides, with a broad spectrum of applications from shrimp processing waste.     

Cyanobacterial biomass as N-supplement to agro-waste for hyper-production of laccase from Pleurotus ostreatus in solid state fermentation

The potential application of dry biomass of a cyanobacterium Anacystis nidulans as a supplement in SSF for the production of laccase from Pleurotus ostreatus was evaluated. Experiments were carried out in solid culture using groundnut shell as a basic substrate supplemented with four independent nitrogen sources (ammonium sulphate, urea, yeast extract and dry powder of cyanobacteria). All the four supplements enhanced the enzyme yield, and yeast extract showed precedence over inorganic nitrogenous sources. However, when dry biomass of A. nidulans was used as an additive to groundnut shell (agricultural residues), it supported maximum cell growth (56.83 ± 5.56 mg/g dry substrate) and laccase production (49.21 ± 4.89 U/g dry substrate). Addition of 1 mM copper salt in the medium containing groundnut shell supplemented with yeast extract gave laccase activity of 32.64 ± 3.4 U/g dry substrate. When dry powder of cyanobacterial biomass was used as N-supplement, laccase production enhanced to 65.42 ± 6.48 U/g dry substrate. In addition to the enhancement to enzyme production inhibitory effects of high concentrations of copper was also diminished in the medium having dry cyanobacterial biomass. This study, forms the first report on the potential application of cyanobacterial biomass as an additive for production of laccase by Pleurotus ostraetus MTCC 1804 in solid state fermentation and has relevance in scale-up production of this fungal enzyme of commercial significance.     

Expression,characterization and mutagenesis of an FAD-dependent glucose dehydrogenase from Aspergillus terreus

An FAD-dependent glucose dehydrogenase (FAD-GDH) from Aspergillus terreus NIH2624 was expressed in Escherichia coli with a yield of 228 ± 16 U/L of culture. Co-expression with chaperones DnaK/DnaJ/GrpE and osmotic stress induced by simple carbon sources enhanced productivity significantly, improving the yield to 23883 ± 563 U/L after optimization. FAD-GDH was purified in two steps with the specific activity of 604 U/mg. Using d-glucose as substrate, the optimal pH and temperature for FAD-GDH were determined to be 7.5 and 50 °C, respectively. Activity was stable across the pH range 3.5–9.0, and the half-life was 52 min at 42 °C. K_m and V_max were calculated as 86.7 ± 5.3 mM and 928 ± 35 U/mg, and the molecular weight was approximately 65.6 kDa based on size exclusion chromatography, indicating a monomeric structure. The 3D structure of FAD-GDH was simulated by homology modelling using the structure of A. niger glucose oxidase (GOD) as template. From the model, His551, His508, Asn506 and Arg504 were identified as key residues, and their importance was verified by site-directed mutagenesis. Furthermore, three additional mutants (Arg84Ala, Tyr340Phe and Tyr406Phe) were generated and all exhibited a higher degree of substrate specificity than the native enzyme. These results extend our understanding of the structure and function of FAD-GDH, and could assist potential commercial applications.     

Covalent immobilization of hydroperoxide lyase on chitosan hybrid hydrogels and production of C6 aldehydes by immobilized enzyme

Five kinds of spacer arm attached chitosan hybrid hydrogels were tested for the possibility of being used as carriers for the immobilization of hydroperoxide lyase from amaranthus tricolor leaves. The 1,6-hexamethylenediamine attached chitosan-κ-carrageenan with biomimetic hydrophobic surface was proved to be the most suitable carrier. A maximum activity of 7.49 ± 0.19 U/g and a yield of 95% were obtained under optimized coupling condition. Meanwhile, the affinity between enzyme and substrates was not reduced after immobilization, as evidenced by the fact that the K_m value of hydroperoxide lyase decreased from 108.6 to 79.97 μM for 13-hydroperoxy-linoleic-acid and almost unchanged for 13-hydroperoxy-linolenic-acid. Furthermore, the thermal, operational and storage stabilities of HPL were significantly improved after immobilization. Using the immobilized enzyme as the catalyst, the yield of 2(E)-hexenal and hexanal reached 1374.8 ± 51.8 mg/L and 1987.9 ± 67.9 mg/L, respectively, and the amount of immobilized enzyme needed in the reaction mixture was much lower than its free counterpart.     

A comparison of the kinetic properties of free and immobilized Aspergillus oryzae β-galactosidase

The objective of this work was to compare the properties of free and immobilized β-galactosidase (Aspergillus oryzae), entrapped in alginate–gelatin beads and cross-linked with glutaraldehyde. The free and immobilized forms of the enzyme showed no decrease in enzyme activity when incubated in buffer solutions in pH ranges of 4.5–7.0. The kinetics of lactose hydrolysis by the free and immobilized enzymes were studied at maximum substrate concentrations of 90 g/L and 140 g/L, respectively, a temperature of 35 °C and a pH of 4.5. The Michaelis–Menten model with competitive inhibition by galactose fit the experimental results for both forms. The K_m and V_m values of the free enzyme were 52.13 ± 2.8 mM and 2.56 ± 0.3 g_glucose/L min mg_enzyme, respectively, and were 60.30 ± 3.3 mM and 1032.07 ± 51.6 g_lactose/min m³_catalyst, respectively, for the immobilized form. The maximum enzymatic activity of the soluble form of β-galactosidase was obtained at pH 4.5 and 55 °C. Alternatively, the immobilized form was most active at pH 5.0 at 60 °C. The free and immobilized enzymes presented activation energies of 6.90 ± 0.5 kcal/mol and 7.7 ± 0.7 kcal/mol, respectively, which suggested that the immobilized enzyme possessed a lower resistance to substrate transfer.     

Biodegradation of Tapis blended crude oil in marine sediment by a consortium of symbiotic bacteria

Biodegradation rate and the high molecular weight hydrocarbons are among the important concerns for bioremediation of crude oil. Inoculation of a non-oil-degrading bacterium as supplementary bacteria increased oil biodegradation from 57.1% to 63.0% after 10 days of incubation. Both the oil-degrading bacteria and the non-oil-degrading bacteria were isolated from Malaysian marine environment. Based on the 16S rDNA sequences, the oil-degrading bacteria was identified as Pseudomonas pseudoalcaligenes (99% similarity) while the non-oil-degrading bacterium was Erythrobacter citreus (99% similarity). E. citreus does not grow on crude oil enriched medium under present experimental condition but it withstands 5000 mg kg^?1 Tapis blended crude oil in sediment. Under optimal condition, the oil-degrading bacterium; P. pseudoalcaligenes, alone utilized 583.3 ± 3.8 mg kg^?1 (57.1%) at the rate of 3.97 × 10^?10 mg kg^?1 cell^?1 day^?1 Tapis blended crude oil from 1000 mg kg^?1 oil-contaminated sediment. Inoculation of E. citreus as the supplementary bacteria to P. pseudoalcaligenes enhanced biodegradation. The bacterial consortium degraded 675.8 ± 18.5 mg kg^?1 (63.0%) Tapis blended crude oil from the 1000 mg kg^?1 oil-contaminated sediment. Biodegradation rate of the bacterial consortium increased significantly to 4.59 × 10^?10 mg kg^?1 cell^?1 day^?1 (p = 0.02). Improvement of the oil degradation by the bacterial consortium was due to the synergetic reaction among the bacterial inoculants. There are two implications: (1) E. citreus may have a role in removing self-growth-inhibiting compounds of P. pseudoalcaligens. (2) P. pseudoalcaligenes degraded Tapis blended crude oil while E. citreus competes for the partially degraded hydrocarbons by P. pseudoalcaligenes. P. pseudoalcaligenes forced to breakdown more hydrocarbons to sustain its metabolic requirement. The bacterial consortium degraded 78.7% of (C₁₂–C₃₄) total aliphatic hydrocarbons (TAHs) and 74.1% of the 16 USEPA prioritized polycyclic aromatic hydrocarbons.     

Demineralization of crab shell waste by Pseudomonas aeruginosa F722

Crab shell (CS) waste samples (particle size 3–10 and 20–35 mm) were inoculated with the newly isolated Pseudomonas aeruginosa F722 to study the efficiency of microbial demineralization (DM) and deproteinization (DP) in the process of extracting chitin. The inoculated waste was incubated for 7 days at 25, 30 and 35 °C. Various concentrations of glucose were supplemented as carbon source. At the optimal temperature of 30 °C, DM was 92% and DP was 63% DP, whereas the pH dropped from initial pH 8.0 to 4.1. In comparative experiments with different amounts of CS waste, 5% CS waste treatment was shown to be the optimal amount for efficient DM. A positive relationship is correlated between DM and glucose concentration (r² = 0.821), whereas a negative relationship is correlated between DM and pH (r² = 0.793). DP and protease activity were little affected by different crab shell sizes.     

Rapid harvesting of freshwater microalgae using chitosan

In this study, chitosan was used as a flocculant to harvest freshwater microalgae Chlorella vulgaris. The recovery efficiency of C. vulgaris was tested at various chitosan concentrations. 120 mg/L of chitosan showed the highest efficiency (92 ± 0.4%) within 3 min. The maximum concentration factor of 10 was also achieved at this dose of chitosan. The harvesting efficiency was pH dependent. pH 6.0 showed the highest harvesting efficiency (99 ± 0.5%). Measurement of zeta-potential confirmed that the flocculation was induced by charge neutralization. This study showed that a biopolymer, chitosan, can be a promising flocculant due to its high efficacy, low dose requirements, and short settling time.     

Purification and characterization of an extracellular antifungal chitinase from Penicillium ochrochloron MTCC 517 and its application in protoplast formation

A highly chitinolytic strain Penicillium ochrochloron MTCC 517 was procured from MTCC, Chandigarh, India. Culture medium supplemented with 1% chitin was found to be suitable for maximum production of chitinase. Purification of extracellular chitinase was done from the culture medium by organic solvent precipitation and DEAE-cellulose column chromatography. The chitinase was purified 6.92-fold with 29.9% yield. Molecular mass of purified chitinase was found to be 64 kDa by SDS-PAGE. The chitinase showed optimum temperature 40 °C and pH 7.0. The enzyme activity was completely inhibited by Hg²⁺, Zn²⁺, K⁺ and NH₄⁺. The enzyme kinetic study of purified chitinase revealed the following characteristics, such as apparent K_m 1.3 mg ml^?1, V_max 5.523 × 10^?5 moles l^?1 min^?1 and K_cat 2.37 s^?1 and catalytic efficiency 1.82 s^?1 M^?1. The enzyme hydrolyzed colloidal chitin, glycol chitin, chitosan, glycol chitosan, N,N′-diacetylchitobiose, p-nitrophenyl N-acetyl-β-d-glucosaminide and 4-methylumbelliferyl N-acetyl-β-d-glucosaminide. The chitinase of P. ochrochloron MTCC 517 is an exoenzyme, which gives N-acetylglucosamine as the main hydrolyzate after hydrolysis of colloidal chitin. Protoplasts with high regeneration capacity were obtained from Aspergillus niger using chitinase from P. ochrochloron MTCC 517. Since it also showed antifungal activity, P. ochrochloron MTCC 517 seems to be a promising biocontrol agent.     

Immobilization of porcine pancreatic lipase on poly-hydroxybutyrate particles for the production of ethyl esters from macaw palm oils and pineapple flavor

Poly-hydroxybutyrate particles (PHB) were used as support to immobilize porcine pancreatic lipase (PPL). The biocatalysts prepared were tested in the synthesis of pineapple flavor by esterification of butanol and butyric acid in heptane medium, and in the synthesis of ethyl esters by transesterification of macaw palm pulp (MPPO) and macaw palm kernel (MPKO) oils with ethanol in solvent-free systems. The effect of protein loading on the biocatalyst activity was assessed in olive oil hydrolysis. Maximum hydrolytic activity of 292.8 ± 8.60 IU/g was observed. Langmuir isotherm model was applicable to the adsorption of PPL on PHB particles. Maximum immobilized protein amount was 24.3 ± 1.70 mg/g. The optimal pH and temperature in hydrolysis reaction for the immobilized PPL were at pH 8.5 and 50 °C, while for the crude PPL extract were at pH 8.0 and 45 °C. Immobilized PPL exhibited full hydrolytic activity after 2 h of incubation in non-polar solvents. In esterification reaction, optimal conversion was around 93% after 2 h of reaction. After six esterification cycles, the biocatalyst retained 63% of its initial activity. The biocatalyst prepared attained transesterification yield of 50% after 48 h of reaction for MPKO and 35% after 96 h of reaction for MPPO.     

High yield preparation of ganglioside GM1 using recombinant sialidase from Cellulosimicrobium cellulans

Cellulosimicrobium cellulans employs extracellular sialidase to selectively convert polysialogangliosides to ganglioside GM1. We cloned this novel sialidase gene (ccsia) from C. cellulans sp. 21, and overexpressed recombinant sialidase (CcSia) protein in E. coli BL21 (DE3) by high cell density fermentation. The presence of an N-terminal hexa-His tag allowed for purification using nickel affinity chromatography (2.3-fold, specific activity 41.5 U/mg). As determined by gel electrophoresis and gel filtration chromatography, the molecular weight of CcSia was found to be about 75 kDa, consistent with sequence analysis (75,271 Da). CcSia transformed polysialogangliosides GD1a, GD1b and GT1b into GM1. For this reaction, the response surface approach showed that optimal conditions in a 1-L system were 2 h incubation at 32.5 °C and pH 5.2, with substrate concentrations of 10 g/L and crude enzyme concentration 1 g/L, respectively. Under above conditions, 10 g/L of ganglioside was completely converted to the product GM1 with a yield of 52%. Our studies demonstrate CcSia could be used for industrial preparation of ganglioside GM1 by the pharmaceutical industry.     

Extraction and characterization of chitin and chitosan from marine sources in Arabian Gulf

Chitin in the α and the β forms has been extracted from different marine crustacean from the Arabian Gulf. The contents of the various exoskeletons have been analyzed and the percent of the inorganic salt (including the various elements present), protein and the chitin was determined. Deacetylation of the different chitin produced was conducted by the conventional thermal heating and by microwave heating methods. Microwave heating has reduced enormously the time of heating from 6–10 h to 10–15 min, to yield the same degree of deacetylation and higher molecular weight chitosan. This technique can save massive amount of energy when implemented on a semi-industrial or industrial scale. The chitin and the obtained chitosan were characterized by elemental analysis, XRD, NMR, FTIR and thermogravimetric measurements. XRD analysis showed that chitosan has lower crystallinity than its corresponding chitin; meanwhile its thermal stability is also lower than chitin.     

Operation of a fixed-bed bioreactor in batch and fed-batch modes for production of inulinase by solid-state fermentation

This work is focused on the inulinase production by solid-state fermentation (SSF) in a fixed-bed reactor (34 cm diameter and 50 cm height) with working capacity of 2-kg of dry substrate operated in batch and fed-batch modes. It was investigated different strategies for feeding the inlet air in the bioreactor (saturated and unsaturated air) as alternative to remove the metabolic heat generated during the microbial growth by evaporative cooling. The kinetic evaluation of the process carried out in batch mode using unsaturated air showed that the evaporative cooling decreasing the mean temperature of the solid-bed, although the enzyme production was lower than that obtained using saturated air. Results showed that maximum enzyme activity (586 ± 63 U gds⁻¹) was obtained in the fed-batch mode using saturated air after 24 h of fermentation. The enzymatic extract obtained by fed-batch mode was characterized and presented optimum temperature and pH in the range of 52–57 °C and 4.8–5.2, respectively. For a temperature range from 40 to 70 °C the enzyme presented decimal reduction time, D-value, ranging from 5748 to 47 h, respectively. For a pH range from 3.5 to 5.5 the enzyme showed good stability, presenting D-values higher than 2622 h. In terms of Michaelis–Mentem parameters were demonstrated that the crude inulinase activity presented higher affinity for substrate sucrose compared to inulin.     

A new fungal peroxidase with alkaline-tolerant,chloride-enhancing activity and dye decolorization capacity

A new fungal peroxidase (Pspd) from Perenniporia subacida was purified by ammonium sulfate precipitation, DEAE-cellulose DE52 anionic exchange and Sepharose GL-6B chromatography, resulting in a high specific activity of 9.138 U mg⁻¹, 3.622-fold higher than that of crude enzyme at the same level. Polyacrylamide gel electrophoresis and UV–vis adsorption spectrum analysis showed that the purified enzyme is a heme-containing monomer with a molecular mass of 43.0 kDa. Optimal peroxidase activity was obtained at pH 5.5 and 30 °C when using 100.0 mM n-propanol as substrate, and under these conditions, the catalytic efficiency (k_cat/K_m) is 1.57 s⁻¹ μM⁻¹. Pspd was inhibited by l-cysteine, dithiothreitol, EDTA and sodium azide, but stimulated by Mn²⁺, Na⁺, Mg²⁺ and K⁺. The enzyme is stable over a broad pH range of 7.0–8.5 after incubation for 72 h, which indicated that the enzyme is lasting alkaline-tolerant. It was worth noting that the chloride at relatively low concentrations can enhance the peroxidase activity, with concomitant increase in substrate affinity. Additionally, Pspd performed high decolorization capability toward structurally various dyes and the capability was independent of the oxidizing mediators, with 75.31% of Neutral Red (50.0 mg L⁻¹) being decolorized by 1.5 U mL⁻¹ pure enzyme after incubation for 72 h. These properties demonstrated that Pspd has potentials for textile dyes decolorization applications.