Treatment of chlorine bleaching effluent using a white-rot fungus

This study was undertaken to better understand the reactions related to fungal treatment of pulp bleaching effluents. Color, COD (chemical oxygen demand), glucose, chloride and ammonium concentration were monitored during the course of treatment of alkali extraction stage liquor (E1) with a white-rot fungus Phanerochaete chrysosporium.The color removal rate was independent on the initial glucose concentration. The earlier used glucose concentration of 10 g l⁻¹ was found to be unnecessary high as the residual glucose accounted for about 50% of the final COD of the effluent. The lowest practical glucose concentration was 2 g l⁻¹. Below this the fungus lost its decolorizing activity in a few days. The lignin-related COD decreased 32% and up to 16.5 mM inorganic chloride was liberated (being 34% increase from the original concentration) from the chlorinated organic material in the effluent in 2 d. The observed rapid depletion of added ammonium nitrogen is believed to indicate a switch of a part of the mycelium to primary growth which leads to higher activity and longer active period of time due to renewal of the cells.     

Decolourisation of a pigment plant effluent by Pycnoporus cinnabarinus in a packed-bed bioreactor

Summary The decolourisation of wastewater from a pigment plant by the white-rot fungus Pycnoporus cinnabarinus was studied in a packed-bed bioreactor. Decolourisation was first observed 48 to 72 h after inoculation and was followed using UV/VIS spectrophotometry. An assessment of the inhibitory properties of the effluent on the growth of Pycnoporus cinnabarinus showed that this fungus can tolerate high levels of potentially toxic waste.     

Decolourisation of a synthetic textile effluent using a bacterial consortium

In the present study we examined the performance of a thermoalkalophilic bacterial consortium, where the predominant strain was Bacillus sp. SF, in the degradation of Reactive Black 5 (RB5). We used a reactor working in continuous mode and investigated the effects of pH, hydraulic retention time (HRT) and several added salts on colour and chemical oxygen demand (COD) reductions. For the chosen operational conditions (pH 9, 55 degrees C and HRT of 12 h) the efficiencies achieved were 91.2 +/- 0.8 % for colour removal and 81.2% for COD removal. The system tolerated, with no significant decrease in colour removal efficiency, 30 g/L Na(2)SO(4), Na(2)CO(3) or NaCl. The latter two salts, however, led to a reduction in COD removal of 30% and 50%, respectively. The system proved to be very effective in the decolourisation of C.I. RB5 under alkaline conditions and at a comparatively high temperature.     

Production of penicillin in a fluidized-bed bioreactor using a carrier-supported mycelial growth

A carrier-supported mycelial growth of Penicillium chrysogenum was applied to penicillin fermentation system using celite as a support material. Hyphal growth through the pore matrices of the material showed strong anchorages and provided highly stable biofilm growth. With bioparticles developed in such a manner, both cell growth and penicillin production were observed to increase significantly compared to the conventional dispersed filamentous cultures. Maximum values of specific penicillin production rate were found to be constant regardless of the growth form. A three-phase fluidized-bed fermentor was designed and tested for penicillin production using the bioparticles. Two modes of operation, semicontinuous and repeated fed batch, of the fermentor were tried. It was noted that the overgrowth of free mycelia and the development of fluffy loose bioparticles caused poor mixing and made the fermentor operation quite difficult. Control of the bioparticle size and the extension of production phase were therefore considered important to maintain the reactor productivity at a desired level. From the results of repeated fed-batch operation it was found that the control of bioparticle size could be successfully achieved by phosphate-limiting culture condition. Penicillin production under this condition was also observed to be maintained at a high level (about 80% of the maximum) for at least 1 month.     

Erythropoietin production from CHO cells grown by continuous culture in a fluidized-bed bioreactor.

A Chinese hamster ovary (CHO) cell line that expresses human erythropoietin (huEPO) was in a 2-L Cytopilot fluidized-bed bioreactor with 400 mL macroporous Cytoline-1 microcarriers and a variable perfusion rate of serum-free and protein-free medium for 48 days. The cell density increased to a maximum of 23 x 10(6) cells/mL, beads on day 27. The EPO concentration increased to 600 U/mL during the early part of the culture period (on day 24) and increased further to 980 U/mL following the addition of a higher concentration of glucose and the addition of sodium butyrate. The EPO concentration was significantly higher (at least 2x than that in a controlled stirred-tank bioreactor, in a spinner flask, or in a stationary T-flask culture. The EPO accumulated to a total production of 28,000 kUnits over the whole culture period. The molecular characteristics of EPO with respect to size and pattern of glycosylation did not change with scale up. The pattern of utilization and production of 18 amino acids was similar in the Cytopilot culture to that in a stationary batch culture in a T-flask. The concentration of ammonia was maintained at a low level (< 2 mM) over the entire culture period. The specific rate of consumption of glucose, as well as the specific rates of production of lactate and ammonia, were constant throughout the culture period indicating a consistent metabolic behavior of the cells in the bioreactor. These results indicate the potential of the Cytopilot bioreactor culture system for the continuous production of a recombinant protein over several weeks.     

Production of cephalosporin C in a fluidized-bed bioreactor

Production of cephalosporin C was investigated in a fluidized-bed bioreactor using bioparticles of Cephalosporium acremonium. Bioparticles were developed by forming a biofilm of growing hyphae around celite particles which contained spores of the microorganism. Production of the antibiotic was significantly improved by using bioparticles over the free mycelial culture, possibly due to the enhanced mass transfer capacity of the bioreactor system and successive generation of highly productive morphological forms of the microorganism. The maximum attainable titer of cephalosporin C from the bioreactor system was almost double that from a jar fermentor operation with a free mycelial culture of the same strain. The biofilm of the bioparticles became unstable as the fermentation proceeded. Morphological differentiation of the microorganism caused a gradual loss of biofilm and an increase of free cells in the culture broth. Additional feeding of a limited amount of methionine to the fermentation broth was not as effective as expected for improving the bioparticle stability. However, repeated use of the bioparticles revealed a strong possibility to improved the overall reactor performance since it allowed an enhanced production of the antibiotic with fewer free cells.     

Glucoamylases of a fungus isolated from a rotting cassava tuber

Summary Aspergillus niger H-9 is a fungal strain isolated from a rotting cassava tuber in Thailand. In the present study, the production of the enzymes was carried out as solid state ricebran-soybean fermentation. Two types of glucoamylases were isolated and purified. The purified glucoamylases were found to be homogenous on 7.5% polyacrylamide gel disc electrophoresis. The molecular weights of glucoamylase I and II were 59,400–72,600 and 43,000–52,600 respectively. The Km values of glucoamylase I and glucoamylase II were 12.5 and 6.25 mg glucose/ml when soluble starch was used as substrate. The optimal pH of both enzymes was 4.0–5.0. The optimum temperatures for the activities of glucoamylase I and glucoamylase II were 60 and 70°C respectively. Both enzymes were stable in the pH range 3.0–6.0 and temperature stable below 50°C. Both glucoamylases were active on various kinds of starch and dextrin including raw starch. Glucoamylase II was, however, found to hydrolyse raw starch better than glucoamylase I.

---

Resumen Aspergillus niger H-9 es una cepa aislada en Tailandia a partir de tuberculos de cassava afectados de podredumbre. En este trabajo la producción de enzimas tuvo lugar mediante fermentación en un medio sólido compuesto por fibra de arroz y soja. Se aislaron y purificaron dos tipos de glucoamilasas. Al realizar una electroforesis en disco de polyacrilamida al 7.5% se observó que las glucoamilasa purificadas eran homogeneas. Los pesos de las glucoamilasas I y II eran respectivamente 59,400–72,600 y 43,000–52,600. Las Km respectivas fueron 12.5 y 6.25 mg ml^–1 cuando se utilizó almidón soluble como substrato. El pH optimo para ambos enzimas fue 4.0–5.0. Las temperaturas óptimas para la glucoamilasa I y la glucoamilasa II fueron respectivamente de 60 y 70°C respectivamente. Ambos enzimas eran estables en el intérvalo de pH 3.0–6.0 y a temperaturas por debajo de 50°C. Los dos enzimas eran activos fiente a distintos tipos de almidón y dextrina incluyendo almidón bruto. La glucoamilasa II hidrolizó mejor el almidón bruto que la glucoamilasa I.

---

Résumé Aspergillus niger H-9 est une souche de moisissure isolée en Thailande à partir de tubercules pourris de manioc. Dans cette étude, la production d'enzymes a été obtenue par fermentation en milieu solide sur son de riz et soja. Deux types de gluco-amylases ont été isolés et purifiés. Les enzymes purifiés sont homogènes en disque-éléctrophorèse sur gel de polyacrylamide. Les poids moléculaires des gluco-amylases I et II sont respectivement de 59,400–72,600 et 43,000–52,000 et leurs Km pour l'amidon soluble de 12.5 et 6.25 mg de glucose/ml. Le pH optimum des deux enzymes est compris entre 4.0 et 5.0. Leurs températures optimales sont respectivement de 60 et 70°C. Les deux enzymes sont stables de pH 3.0–6.0 et aux températures inférieures à 50°C. Les deux gluco-amylases sont actives sur différents types d'amidon et de dextrines, y compris l'amidon cru. Toutefois, la gluco-amylase II hydrolyse l'amidon cru plus activement que la gluco-amylase I.

---

---

Paper presented at the VII International Conference on the Global Impacts of Applied Microbiology, Helsinki, 12–16 August 1986.     

Decolourisation of effluent from the textile industry by a microbial consortium

Summary A microbial consortium, PDW, was isolated capable of the rapid decolourisation of commercially important textile dyes under anaerobic conditions. Decolourisation was dependent upon the presence of a carbon and energy source in addition to the textile dyes. PDW was capable of dye decolourisation when utilising cheap and readily available carbon sources such lactose, starch and distillery waste. PDW removed 76% of colour from textile plant effluent after 3 days.     

Hydrodynamic characteristics of immobilized cell beads in a liquid-solid fluidized-bed bioreactor

This study examined the hydrodynamic characteristics of a liquid-solid fluidized-bed bioreactor using elastic particles (PVA gel beads) of various diameters as carriers. The drag coefficient-Reynolds number, velocity-voidage, and expansion index-Reynolds number relationships observed during fluidization of PVA gel beads in a fluidized bed in our experiments were compared with the published results. Predictions made from previous correlations were examined with our new experimental findings, revealing the inadequacy of most of these correlations. Thus, new correlations describing the above-mentioned relationships are suggested. The drag coefficient of immobilized cell beads is larger than that of free cell ones at the same Reynolds number because the surface of the immobilized cell beads is rougher. For multiparticle systems, the correction factor, f(epsilon), is a function of the falling gel bead properties (Reynolds number) as well as the fluidized gel bead properties (Archimedes number), and depend strongly on the bed voidage (epsilon). A new simple relation was developed to predict easily the epsilon value from 0.5-0.9 at 4,986 < A(r) < 40,745 or 34 < Re(t) < 186. For all the immobilized cell beads used in this study, the prediction error of the bed voidage was less than 5% at epsilon > 0.5. The prediction equations in this study can be further applied to analyzing the hydrodynamic characteristics of a fluidized-bed reactor using similar entrapped elastic particles as carriers.     

Decolourisation of synthetic and spentwash melanoidins using the white-rot fungus Phanerochaete chrysosporium JAG-40

Phanerochaete chrysosporium JAG-40 was isolated from the soil samples saturated with spilled molasses collected from a sugar mill. This isolate decolourised synthetic and natural melanoidins present in spentwash in liquid fermentation; up to 80% in 6 days at 30 degrees C under aerobic conditions. A large inoculum size stimulated fungal biomass production, but this gave less decolourisation of pigment; 5% w/v (dry weight) mycelial suspension was found optimum for maximum decolourisation in melanoidin medium supplemented with glucose and peptone. Gel-filtration chromatography showed that larger molecular weight fractions of melanoidin were decolourised more rapidly than small molecular weight fractions.     

Nitrate removal from drinking water in a fluidized-bed biological denitrification bioreactor

In most industrially developed countries an increasing degree of nitrification can be observed in potential water reservoirs. High nitrate content is unacceptable by public health standards. Since contamination seems to be unavoidable, the only realistic solution is purification prior to utilization. One of the potential variations is biological denitrification with a highly intensive facility, a fluidized- or expanded-bed bioreactor. Based on laboratory and pilot plant experiments, a detailed analysis is presented on the problems arising and solutions offered in the construction of a purification system meeting high quality requirements of drinking water purification. The crucial point is selection of the denitrifying microorganisms and organic matter required for denitrification, which simultaneously determines the attachment of bacteria to the support material (autoimmobilization), the intensity of nitrate removal and the character of post-purification.     

Petroleum-contaminated water treatment in a fluidized-bed bioreactor with immobilized Rhodococcus cells

Biotreatment of petroleum-contaminated water in a fluidized-bed bioreactor (FBB) is a relatively new and promising technology, which efficiency is strongly affected by the biocatalyst used. Our laboratory experiments involved biotreatment of the water contaminated with a synthetic petroleum mixture consisting of aliphatic and polyaromatic hydrocarbons (PAHs) using a continuous column bioreactor with recycle. Different type biocatalysts were tested, including Rhodococcus bacteria immobilized in hydrophobized carriers such as sawdust, poly(vinyl alcohol) cryogel (cryoPVA) and poly(acrylamide) cryogel (cryoPAAG). Biocatalyst abilities to oxidize petroleum hydrocarbons were evaluated using the Columbus Micro-Oxymax^® respirometer. The hydrophobized sawdust-supported biocatalyst demonstrated substantially higher metabolic activity than C₁₂-cryoPAAG-based biocatalyst due to larger number of immobilized Rhodococcus cells and, therefore, had benefits for application in FBBs. The obtained results showed that designed FBB process is successful, providing 70–100% removal of n-alkanes (C₁₀–C₁₉) and 66–70% removal of 2–3-ring PAHs from contaminated water after 2–3 weeks.     

Dynamics of a biological fixed film for phenol degradation in a fluidized-bed bioreactor

Experimental and modeling studies were conducted to analyze the dynamic response behavior of a phenol-oxidizing fixed film using a differential, fluidized-bed bioreactor in a recycle loop with a well-mixed reservoir. With the bioreactor at steady state, a pulse of phenol was added to perturb the system, and the phenol concentration was monitored continuously until steady state was again achieved.The experimental dynamics were compared with a dynamic mathematical model based on diffusion and reaction within the biofilm, liquid mixing, and biofilm growth. Constant-pH experiments could be adequately described using an unstructured, double-Monod kinetic expression with substrate inhibition by phenol.However, in dynamic experiments without pH control, the pH of the liquid phase dropped, and damped oscillations were observed in the phenol concentration and reaction rate trajectories. Oscillatory solutions could not be induced in the model, even when product inhibition was included, and a linear stability analysis did not reveal tendencies toward instability. The cause of the experimental oscillations remains unknown.     

Colour removal from bagasse-based pulp mill effluent using a white rot fungus

Colour removal of pulp plant effluent was studied using white rot fungus, Trametes (Coriolus) versicolor. The batch experiments were carried out using fungus in the form of mycelial pellets. In the present investigation, the effect of pH, concentrations of glucose (substrate), initial effluent colour and ammonium chloride (nutrient) on colour removal efficiency were studied. It was found that the maximum colour removal efficiency of 82.5% was obtained with an optimal glucose and ammonium chloride concentrations of 15 g/l and 0.5 g/l respectively at a pH of 4.5 without diluting the effluent.     

Concentration multiplicity in a draft tube fluidized-bed bioreactor involving two limiting substrates

Concentration multiplicity in a two-phase or three-phase draft tube fluidized-bed bioreactor containing biofloc particles is studied. The kinetics of biological reactions considered involve two limiting substrates. The necessary and sufficient conditions for concentration multiplicity in both the biofilm and bioreactor are examined in terms of effectiveness factor, inlet and bulk concentration of substrates, and liquid flow rate. Hysteresis behavior in both the biofilm and bioreactor and multiplicity of concentration profiles in the biofilm are also discussed.     

Development of a bioreactor system using an immobilized white rot fungus for decolorization

In this research the wood-rotting fungus Phanerochaete chrysosporium culture was shown to be immobilized very well on the porous foam material. The biomass concentration increased to about 2–3 g/l in 4–5 days. Repeated-batch decolorization tests using immobilized Phanerochaete chrysosporium cells were conducted for 16 days with initial concentrations of 50–500 ppm of Red 533 dispersed dye, a decolorization efficiency of 80% or higher was achieved within a period of one or two days. The ability of the immobilized culture to perform a long-term decolorization operation was confirmed. The authors wish to thank I.T.R.I. and the National Science Council of R.O.C. for financial supports.     

Development of a bioreactor system using an immobilized white rot fungus for decolorization

In this paper the fixed film reactor system containing immobilized Phanerochaete chrysosporium cells was employed for decolorization of Red 533 dispersed dye. The inlet dye concentration and the inlet flow rate were shown to affect the decolorization efficiency. Each decolorization process was conducted continuously for 10–20 days or more and the decolorization efficiency remained higher than 80%. The immobilized cultures possessed good biological activities and the biodegrading system also showed capability for a long term operation.     

漂白废水中关键有毒物质鉴别的实例研揪

以纸张漂白废水为研究对象,采用毒性鉴别评价(TIE, Toxicity Identification     

Contamination of a high-cell-density continuous bioreactor

Continuous fermentations were carried out with a recombinant flocculent Saccharomyces cerevisiae strain in an airlift bioreactor. Once operating under steady state at a dilution rate of 0.45 h(-1), the bioreactor was contaminated with Escherichia coli cells. The faster growing E. coli strain was washed out of the bioreactor and the recombinant, slower growing flocculating S. cerevisiae strain remained as the only species detected in the bioreactor. Flocculation, besides allowing for the realization of high-cell-density systems with corresponding unusual high productivity, may be used as a selective property for controlling some contamination problems associated with prolonged continuous operation.