Effect of the aeration rate and agitation speed on β-carotene production and morphology of Blakeslea trispora in a stirred tank reactor: mathematical modeling

The effect of aeration rate and agitation speed on β-carotene production and morphology of Blakeslea trispora in a stirred tank reactor was investigated. B. trispora formed hyphae, zygophores and zygospores during the fermentation. The zygospores were the morphological form responsible for β-carotene production. Both aeration and agitation significantly affected β-carotene concentration, productivity, biomass and the volumetric mass transfer coefficient (K_La). The highest β-carotene concentration (1.5 kg m⁻³) and the highest productivity (0.08 kg m⁻³ per day) were obtained at low impeller speed (150 rpm) and high aeration rate (1.5 vvm). Also, maximum productivity (0.08 kg m⁻³ per day) and biomass dry weight (26.4 kg m⁻³) were achieved at high agitation speed (500 rpm) and moderate aeration rate (1.0 vvm). Conversely, the highest value of K_La (0.33 s⁻¹) was observed at high agitation speed (500 rpm) and high aeration rate (1.5 vvm). The experiments were arranged according to a central composite statistical design. Response surface methodology was used to describe the effect of impeller speed and aeration rate on the most important fermentation parameters. In all cases, the fit of the model was found to be good. All fermentation parameters (except biomass concentration) were strongly affected by the interactions among the operation variables. β-Carotene concentration and productivity were significantly influenced by the aeration, agitation, and by the positive or negative quadratic effect of the aeration rate. Biomass concentration was principally related to the aeration rate, agitation speed, and the positive or negative quadratic effect of the impeller speed and aeration rate, respectively. Finally, the volumetric mass transfer coefficient was characterized by the significant effect of the agitation speed, while the aeration rate had a small effect on K_La.     

Agitation,aeration and shear stress as key factors in inulinase production by Kluyveromyces marxianus

Factorial design and response surface analyses were used to optimize the production of inulinase (2,1-β-d-fructan fructanohydrolase, EC 3.2.1.7) by Kluyveromyces marxianus ATCC 16045, using sucrose as carbon source. Effects of aeration, agitation and type of impeller (disk turbine, marine, pitched blade) were studied in a batch stirred reactor. Two factorial designs 2² were carried out. Agitation speed varied from 50 to 550 rpm (revolution per minute), aeration rate from 0.5 to 2.0 vvm (air volume/broth volume·minute). It has been shown that the enzyme production was strongly influenced by mixing conditions, while aeration rate was shown to be less significant. Additionally, the increase in the agitation speed is limited by the death rate, which increases drastically at high speeds, lowering the enzyme production. Also, the impeller type has significant influence in the production, the disk impeller at 450 rpm and aeration at 1.0 vvm led to an activity of 121 UI/mL, while the pitched blade was shown to be the best impeller for this process, leading to the best production, 176 UI/mL, at 450 rpm and 1.0 vvm. The maximum shear stress for inulinase production was about 0.22 Pa, since higher values cause higher cell death rates, affecting the enzyme production. The same results were confirmed with another microorganism, which was also sensible to shear stress. Therefore, it has been concluded that in some cases, mainly when the microorganism is sensible to shear stress, the interaction between mass transfer and mechanical stress should be considered in scale up processes.     

Fermentation strategies for the production of lipase by an indigenous isolate Burkholderia sp. C20

Burkholderia sp. C20 strain isolated from food wastes produces a lipase with hydrolytic activities towards olive oil. Fermentation strategies for efficient production of this Burkholderia lipase were developed using a 5-L bench top bioreactor. Critical factors affecting the fermentative lipase production were examined, including pH, aeration rate, agitation rate, and incubation time. Adjusting the aeration rate from 0.5 to 2 vvm gave an increase in the overall lipase productivity from 0.057 to 0.076 U/(ml h), which was further improved to 0.09 U/(ml h) by adjusting the agitation speed to 100 rpm. The production of Burkholderia lipase followed mixed growth-associated kinetics with a yield coefficient of 524 U/g-dry-cell-weight. The pH optimum for cell growth and lipase production was different at 7.0 and 6.0, respectively. Furthermore, stepwise addition of carbon substrate (i.e., olive oil) enhanced lipase production in both flask and bioreactor experiments.     

Scale-up of micro-aerobic 1,3-propanediol production with Klebsiella pneumonia CGMCC 1.6366

The conversion of glycerol to 1,3-propanediol (1,3-PD) using Klebsiella pneumoniae CGMCC 1.6366 under aerobic condition was scaled up from scale 5 to 50,000 l in series. Several parameters including power input P/V_l, agitation rate n, impeller tip speed nD, superficial gas velocity u_s, and Re_s were investigated as the criteria for scaling up. Impeller tip speed was chosen as the main criterion. It was also noticed less aeration was favored in that less electron will be shunted to electron transfer chain. The fermentation in 500 l bioreactor produced 66.8 g 1,3-PD with the yield of 0.55 mol mol^?1 at agitation rate and aeration of 130 rpm and 0.14 vvm air flow. Using these empirically obtained control concepts we successfully scaled up in 500–50,000 l pilot-scale reactors. The final 1,3-PD concentrations in 50,000 l bioreactor amounted to 63.3 g l^?1 with the yield of 0.5 mol mol^?1.     

The effect of agitation and aeration on the synthesis and molecular weight of gellan in batch cultures of Sphingomonas paucimobilis

The effects of agitation and aeration upon synthesis and molecular weight of the biopolymer gellan were systematically investigated in batch fermenter cultures of the bacterium, Sphingomonas paucimobilis. High aeration rates and vigorous agitation enhanced growth of S. paucimobilis. Although gellan formation occurred mainly in parallel with cell growth, the increase in cells able to synthesise gellan did not always lead to high gellan production. For example, at very high agitation rates (1000 rpm) growth was stimulated at the expense of biopolymer synthesis.Maximal gellan concentration was obtained at 500 rpm agitation and either 1 or 2 vvm aeration (12.3 and 12.4 g/l gellan, respectively). An increase in aeration (from 1 to 2 vvm) enhanced gellan synthesis only at low agitation rates (250 rpm). However, high aeration or dissolved oxygen was not necessary for high gellan synthesis, in fact oxygen limitation always preceded the phase of maximum gellan production and probably enhanced polysaccharide biosynthesis.Some gellan was formed even after glucose exhaustion. This was attributed to the intracellular accumulation of polyhydroxyalkanoates, (such as polyxydroxybutyrate) which were found in S. paucimobilis cells indicating the existence of a carbon storage system, which may contribute to gellan biosynthesis under glucose-limiting conditions.The autolysis of the culture, which occurred at the late stages of the process, seemed to be triggered mainly by limitations in mass (nutrient) transfer, due to the highly viscous process fluid that gradually develops. Rheological measurements generally gave a very good near real time estimate of maximum biopolymer concentration offering the possibility of improved process control relative to time consuming gravimetric assay methods.While mechanical depolymerisation of gellan did not occur, high aeration rates (2 vvm) led to production of gellan of low molecular weight (at either 250 or 500 rpm). This effect of aeration rate upon gellan molecular weight is reported here for the first time, and is important for the properties and applications of gellan. Mechanisms which may have led to this are discussed, but control of molecular weight of the biopolymers is clearly an area needing further research.     

Production of polysaccharide–peptide complexes by submerged mycelial culture of an entomopathogenic fungus Cordyceps sphecocephala

The effects of medium components and environmental factors on the production of mycelial biomass and polysaccharide–peptide complexes (exobiopolymers) by Cordyceps sphecocephala J-201 were investigated in submerged cultures. The optimal temperature and initial pH for the production of both mycelial biomass and exobiopolymers in flask cultures were found to be 25 °C and pH 4–5, respectively. The optimal combination of the media constituents was as follows (g l⁻¹): sucrose 40, yeast extract 6, polypepton 2, KH₂PO₄ 0.46, K₂HPO₄ 1, and MgSO₄·7H₂O 0.5. The results of bioreactor culture revealed that the maximum concentration of mycelial biomass (28.2 g l⁻¹) was obtained at an agitation speed of 300 rpm and at an aeration rate of 2 vvm, whereas maximum exobiopolymer production (2.5 g l⁻¹) was achieved at a milder agitation speed (150 rpm). There was a significant variance in mycelial morphology between different aeration conditions. Looser mycelial pellets were developed, and their size and hairiness increased as the aeration rate increased from 0.5 to 2.0 vvm, resulting in enhanced exobiopolymer production. The apparent viscosities of fermentation broth increased rapidly towards the end of fermentations at the conditions of high aeration rate and agitation speed, which were mainly due to high amount of mycelial biomass rather than exobiopolymers at the later stages of fermentation. The three different exobiopolymers (FR-I, -II, and -III) were fractionated by a gel filtration chromatography on Sepharose CL-6B. The carbohydrate and protein contents in each fraction were significantly different and the molecular weights of FR-I, FR-II, and FR-III were determined to be 1831, 27, and 2.2 kDa, respectively. The compositional analysis revealed that the three fractions of crude exobiopolymers consisted of acidic and nonpolar amino acids, such as aspartic acid, glutamic acid, glycine, and valine in protein moiety, and of mainly mannose and galactose in sugar moiety.     

Effect of process parameters on lipase production by Candida cylindracea in stirred tank bioreactor using renewable palm oil mill effluent based medium

A two-level full factorial design (FFD) was employed to determine the effects of process parameters on lipase production by Candida cylindracea ATCC 14830 in palm oil mill effluent (POME)-based medium. Ten experimental runs based on three parameters (temperature, agitation and aeration) as indicated by the FFD were carried out in a stirred-tank bioreactor. On statistical analysis of the results, the optimum temperature, aeration and agitation rates were found to be 30 °C, 1.0 vvm and 400 rpm respectively, with a maximum activity of 41.46 U/ml after 36 h of fermentation. Analysis of variance (ANOVA) showed a high coefficient of determination (R²) value of 0.999, indicating a satisfactory fit of the model with the experimental data. All the three parameters were statistically significant at p < 0.05. The validation experiment also confirmed that apart from lipase production, there was an increase in chemical oxygen demand (COD) removal throughout the fermentation period.     

Xylitol production in a bubble column bioreactor: Influence of the aeration rate and immobilized system concentration

This work evaluated the xylitol production from sugarcane bagasse hemicellulosic hydrolysate in a bubble column bioreactor using cells of the yeast Candida guilliermondii immobilized in calcium-alginate. The fermentation runs were performed according to a 2² full factorial design with three replicates at the center point in order to determine the effect of the variables: aeration rate (0.66–1.33 vvm) and immobilized system concentration (20–40% v/v), on the efficiency of xylose-to-xylitol conversion and on the xylitol volumetric productivity. The results indicated a significant influence of both variables on xylitol production. The highest conversion efficiency (41%) was attained using 1.33 vvm aeration rate and 40% immobilized system. Under these conditions, the volumetric productivity was 0.21 g l⁻¹ h⁻¹.     

High bioreactor production and emulsifying activity of an unusual exopolymer by Chromohalobacter canadensis 28

Unusual composition of an exopolymer (EP) from an obligate halophilic bacterium Chromohalobacter canadensis 28 has triggered an interest in development of an effective bioreactor process for its production. Its synthesis was investigated in 2‐L bioreactor at agitation speeds at interval 600‐1000 rpm, at a constant air flow rate of 0.5 vvm; aeration rates of 0.5, 1.0, and 1.5 vvm were tested at constant agitation rate of 900 rpm. EP production was affected by both, agitation and aeration. As a result twofold increase of EP yield was observed and additionally increased up to 3.08 mg/mL in a presence of surfactants. For effective scale‐up of bioreactors mass transfer parameters were estimated and lowest values of K_La obtained for the highest productivity fermentation was established. Emulsification activity of EP exceeded that of trade hydrocolloids xanthan, guar gum, and cellulose. A good synergism between EP and commercial cellulose proved its potential exploration as an enhancer of emulsifying properties of trade emulsions. A pronounced lipophilic effect of EP was established toward olive oil and liquid paraffin. Cultivation of human keratinocyte cells (HaCaT) with crude EP and purified γ‐polyglutamic acid (PGA) showed higher viability than control group.     

Fed-batch culture of recombinant Saccharomyces cerevisiae for glucose 6-phosphate dehydrogenase production

We examined glucose 6-phosphate dehydrogenase (G6PD) production by fed-batch cultivation, using a recombinant strain of Saccharomyces cerevisiae W303-181 overexpressing this enzyme. The cultivations were carried out in a 3 L fermenter at pH 5.7, 30 °C, 2.0 vvm aeration, 200 rpm agitation and an inoculum concentration of 1.0 g/L. The volume of the culture medium in the fed-batch process varied from 1.333 to 2.0 L, due to the addition of 15.0 g/L glucose solution during 5 h. Different feeding rates were studied (exponentially increasing and decreasing feeding rates), and the feeding profile was determined by values of the parameter K (time constant), namely: 0.2, 0.5 and 0.8 h⁻¹. The best enzyme production (847 U/L) was obtained with an exponentially increasing feeding rate and K = 0.2 h⁻¹. The results attained also showed that this process is promising for G6PD production.     

Effects of pellet morphology on broth rheology in fermentations of Aspergillus terreus

Effects of pellet morphology on broth rheology are reported for pelleted submerged cultures of the lovastatin producing filamentous fungus Aspergillus terreus, growing in fluidized bed and stirred tank bioreactors. The pellet diameter and compactness were affected by the agitation intensity of the broth; however, the total biomass productivity was not affected. In fluidized beds and stirred tanks with agitation intensity of up to 300 rpm (impeller tip speed of 1.02 m s⁻¹), the fungal pellets were stable at diameters of up to about 2300 μm. In more intensely agitated stirred tanks (≥600 rpm; impeller tip speed of ≥2.03 m s⁻¹), the stable pellet size was only about ≤900 μm. The biomass concentration and the pellet diameter were the main factors that influenced the flow index and the consistency index of the power-law broths. Because the biomass productivity was the same in all experiments in a given type of reactor and the oxygen concentration was kept at ∼400% of air saturation, the pellet size and morphology were not influenced by oxygen mass transfer effects. Pellets were always dense in the core region and no necrosis of the biomass occurred.     

l-Lactic acid production from liquefied cassava starch by thermotolerant Rhizopus microsporus: Characterization and optimization

The thermotolerant Rhizopus microsporus DMKU 33 capable of producing l-lactic acid from liquefied cassava starch was isolated and characterized for its phylogenetic relationship and growth temperature and pH ranges. The concentrations of (NH₄)₂SO_4, KH₂PO₄, MgSO₄ and ZnSO₄·7H₂O in the fermentation medium was optimized for lactic acid production from liquefied cassava starch by Rhizopus microsporus DMKU 33 in shake-flasks at 40 °C. The fermentation was then studied in a stirred-tank bioreactor with aeration at 0.75 vvm and agitation at 200 rpm, achieving the highest lactic acid production of 84 g/L with a yield of 0.84 g/g at pH 5.5 in 3 days. Lactic acid production was further increased to 105–118 g/L with a yield of 0.93 g/g and productivity of 1.25 g/L/h in fed-batch fermentation. R. microsporus DMKU 33 is thus advantageous to use in simultaneous saccharification and fermentation for l-lactic acid production from low-cost starchy substrates.     

Mixed culture of Saccharomyces cerevisiae and Acetobacter pasteurianus for acetic acid production

Mixed culture of Saccharomyces cerevisiae and Acetobacter pasteurianus was carried out for high yield of acetic acid. Acetic acid production process was divided into three stages. The first stage was the growth of S. cerevisiae and ethanol production, fermentation temperature and aeration rate were controlled at 32 °C and 0.2 vvm, respectively. The second stage was the co-culture of S. cerevisiae and A. pasteurianus, fermentation temperature and aeration rate were maintained at 34 °C and 0.4 vvm, respectively. The third stage was the growth of A. pasteurianus and production of acetic acid, fermentation temperature and aeration rate were controlled at 32 °C and 0.2 vvm, respectively. Inoculation volume of A. pasteurianus and S. cerevisiae was 16% and 0.06%, respectively. The average acetic acid concentration was 52.51 g/L under these optimum conditions. To enhance acetic acid production, a glucose feeding strategy was subsequently employed. When initial glucose concentration was 90 g/L and 120 g/L glucose was fed twice during fermentation, acetic acid concentration reached 66.0 g/L.     

Evaluation of biocomposite-based supports for immobilized-cell xylitol production compared with a free-cell system

This study was conducted to evaluate the importance of aeration in free and immobilized cell systems in an aerated bioreactor for xylitol production from an oat hull hemicellulosic hydrolysate using an integrated process. The aeration rate (AR) or oxygen mass transfer coefficient (k_La) demonstrated a significant role in controlling cell (Candida guilliermondii FTI 20037) regeneration and bioconversion performance in free and immobilized cell systems. In the free cell system, an aeration rate of 1.25 vvm corresponding to k_La of 15.8 1/h resulted in maximum values of product yield (Y_p/s: 0.87 g/g), productivity (Q_p: 0.57 g/l/h), and final xylitol concentration (P_f: 55 g/l) from the hydrolysate with a 74.5 g/l xylose concentration. However, in the aerated immobilized cell system, maximum and almost similar results (almost P_f: 54 g/l, Q_p: 0.57 g/l/h and Y_p/s: 0.84 g/g) were obtained with aeration rates from 1.25 to 1.5 vvm using composites based on polypropylene (PP) and partially delignified fiber (PDF). Composites based on acid treated fiber (ATF) containing a high amount of lignin showed some inhibitory impact on xylose uptake and xylitol formation (P_f: 47 g/l and Q_p < 0.49 g/l/h) with the optimal aeration rate of 1.5 vvm in the initial cycle of the bioconversion; this inhibition impact could be resolved in the next consecutive cycles. The surface modifier polyethyleneimine (PEI) slightly enhanced cell retention in the immobilized form on the ATF-based cell support. This investigation helps fill in the knowledge gaps existing on the integrated processing of the lignocellulosic biomass for xylitol bioproduction and biorefinery industry; however, more scale-up studies are recommended for commercialization.     

Lipolytic enzyme production by Thermus thermophilus HB27 in a stirred tank bioreactor

In this study, lipolytic enzyme production by Thermus thermophilus HB27 at bioreactor scale has been investigated. Cultivation was performed in a 5-L stirred tank bioreactor in discontinuous mode, at an agitation speed of 200 rpm. Different variables affecting intra- and extra-cellular lipolytic enzyme production such as culture temperature and aeration rate have been analysed. The bacterium was able to grow within the temperature range tested (from 60 to 70 °C) with an optimum value of 70 °C for intra- and extra-cellular lipolytic enzyme production.On the other hand, various aeration levels (from 0 to 2.5 L/min) were employed. A continuous supply of air was necessary, but no significant improvement in biomass or enzyme production was detected when air flow rates were increased above 1 L/min. Total lipolytic enzyme production reached a maximum of 167 U/L after 3 days, and a relatively high concentration of extra-cellular activity was detected (40% of the total amount). Enzyme yield was around 158 U/g cells. Moreover, it is noteworthy that the lipolytic activity obtained operating at optimal conditions (70 °C and air flow of 1 L/min) was about five-fold higher than that attained in shake flask cultures     

Thermo- and mesophilic aerobic batch biodegradation of high-strength distillery wastewater (potato stillage) – Utilisation of main carbon sources

The aim of the study was to ascertain the extent to which temperature influences the utilisation of main carbon sources (reducing substances determined before and after hydrolysis, glycerol and organic acids) by a mixed culture of thermo- and mesophilic bacteria of the genus Bacillus in the course of aerobic batch biodegradation of potato stillage, a high-strength distillery effluent (COD = 51.88 g O₂/l). The experiments were performed at 20, 30, 35, 40, 45, 50, 55, 60 and 63 °C, at pH 7, in a 5 l working volume stirred-tank bioreactor (Biostat^®B, B. Braun Biotech International) with a stirrer speed of 550 rpm and aeration at 1.6 vvm. Particular consideration was given to the following issues: (1) the sequence in which the main carbon sources in the stillage were assimilated and (2) the extent of their assimilation achieved under these conditions.     

Kinetic modeling and implementation of superior process strategies for β-galactosidase production during submerged fermentation in a stirred tank bioreactor

This paper reports development and implementation of superior fermentation strategies for β-galactosidase production by Lactobacillus acidophilus in a stirred-tank bioreactor. Process parameters (aeration and agitation) were optimized for the process by application of Central Composite Design. Aeration rate of 0.5 vvm and agitation speed of 250 rpm were most suitable for β-galactosidase production (2001.2 U/L). Further improvement of the operation in pH controlled environment resulted in 2135 U/L of β-galactosidase with productivity of 142.39 U/L h. Kinetic modeling for biomass and enzyme production and substrate utilization were carried out at the aforementioned pH controlled conditions. The logistic regression model (X₀ = 0.01 g/L; X_max = 2.948 g/L; μ_max = 0.59/h; R² = 0.97) was used for mathematical interpretation of biomass production. Mercier's model proved to be better than Luedeking–Piret model in describing β-galactosidase production (P₀ = 0.7942 U/L; P_max = 2169.3 U/L; P_r = 0.696/h; R² = 0.99) whereas the latter was more efficient in mathematical illustration of lactose utilization (m = 0.187 g/g h; Y_x/s = 0.301 g/L; R² = 0.98) among the two used in this study. Strategies like fed-batch fermentation (3694.6 U/L) and semi-continuous fermentation (5551.9 U/L) further enhanced β-galactosidase production by 1.8 and 2.8 fold respectively.     

Production of an oxidant and SDS-stable alkaline protease from an alkaophilic Bacillus clausii I-52 by submerged fermentation: Feasibility as a laundry detergent additive

An investigation was carried out on enzyme production of an oxidant and SDS-stable alkaline protease secreted by Bacillus clausii I-52 using the submerged fermentation and its application as a detergent additive. Maximum enzyme activity was produced when cells were grown under the submerged fermentation conditions at 37 °C for 48 h with an aeration rate of 1.5 vvm and agitation rate of 700 rpm in a medium (pH 10.65) containing (w/v): soybean meal, 20; wheat flour, 10; liquid maltose, 25; K₂HPO₄, 4; Na₂HPO₄, 1; MgSO₄·7H₂O, 0.1; NaCl, 4; FeSO₄·7H₂O, 0.5; Na₂CO₃, 6. The alkaline protease produced was found to be highly compatible and stable against not only the commercial detergent components such as α-orephin sulfonate and zeolite but also the commercial detergent preparations. Wash performance analysis using EMPA test fabrics revealed that BCAP exhibited high efficiency for the removal of protein stains in the presence of commercial detergents as well as surfactants. These results suggest that the alkaline protease produced from B. clausii I-52 which showed high stability against detergents has significance for an industrial perspective, especially, detergent additive.     

Effect of mechanical agitation on the production of cellulases by Trichoderma reesei RUT-C30 in a draft-tube airlift bioreactor

With the aim to produce cellulases and to study the effect of mechanical agitation, a 35 L draft-tube airlift bioreactor equipped with a mechanical impeller was developed and validated to grow Trichoderma reesei RUT-C30 in a cellulose culture medium with lactose and lactobionic acid as fed batch. Cultures carried out without mechanical agitation resulted in higher volumetric enzyme productivity (200 U L⁻¹ h⁻¹), filter paper activity (17 U mL⁻¹), carboxymethyl cellulase activity (11.8 U mL⁻¹) and soluble proteins (3.2 mg mL⁻¹) when compared to those with agitation. Stereo and polarized light microscopy analyses reveal that mechanical agitation resulted in shorter mycelial hyphae and larger numbers of tips.     

Co-remediation of pentachlorophenol and Cr6+ by free and immobilized cells of native Bacillus cereus isolate: Spectrometric characterization of PCP dechlorination products,bioreactor trial and chromate reductase activity

In this study, Bacillus cereus isolate efficiently remediated 57% PCP and 74% Cr⁶⁺ simultaneously with uptake rate of 0.65 mg Cr⁶⁺ g^?1 biomass h^?1 at initial 200 mg Cr⁶⁺ and 500 mg PCP l^?1 concentration under optimized 0.4% glucose, 0.2% NH₄Cl, pH 7.0, 35 °C, 1.0% inoculum during 60 h incubation. Optimization of agitation (100 rpm) and aeration (0.6 vvm) in bioreactor further enhanced PCP dechlorination by ～5.0% and Cr⁶⁺ removal 7.5%. Presence of other heavy metals variedly affected bioremediation of both the toxicants. Maximum and minimum inhibition was exhibited by mercury and lead, respectively. Out of 74% Cr⁶⁺ remediated, 90% reduced to Cr³⁺, of which 52.8% was associated with cell biomass and 37.2% with culture supernatant. Maximum chromate reductase activity was evident in culture supernatant followed by cytosolic fraction and cell debris. A direct correlation existed between chromate reductase activity and reduced Cr³⁺ in different cell fractions. Among matrices, alginate was most suitable for biomass immobilization, which enhanced Cr⁶⁺ removal by 20.2% compared to free cells at 36 h. Gas chromatography and mass spectrometry detected 2,3,4,6-tetrachlorophenol, 2,4,6-trichlorophenol, 2,6-dichlorophenol and 6-chlorohydroxyquinol as PCP dechlorination products. Our promising strain can be efficiently employed for simultaneous bioremediation of PCP and Cr⁶⁺ under wide environmental conditions.