Biomass Support Particles Research Articles

Continuous IgG production by myeloma cells immobilized within porous support particles

IgG production kinetics of mouse myeloma MPC-11 cells immobilized within porous polyvinyl formal resin biomass support particles (BSPs) was evaluated by monitoring of lactate dehydrogenase activities and IgG concentration in a perfusion culture of the cells. Cells immobilized within the BSPs could stably maintain a high specific IgG production rate, comparable to the maximum production rate in a static culture of non-immobilized MPC-11 cells, over a long period.

Significance of biomass support particles in laboratory studies on microbial degradation of organic chemicals in aquifers

In degradation studies of xenobiotics in groundwater environments from where only water samples can be obtained (e.g. established deep groundwater wells, inhomogeneous formations as boulder aquifers, or consolidated aquifers), solids might be added as biomass support materials. The importance of biomass support materials as quartz sand, rock wool and crushed tiles on the degradation of 8 aromatic hydrocarbons (benzene, toluene, o-xylene, 1,2-dichlorobenzene (1,2-DCB), 1,4-dichlorobenzene (1,4-DCB), naphthalene, biphenyl and nitrobenzene) was investigated in experiments with groundwater collected from two aerobic aquifers (Vejen and Grindsted, Denmark). Experiments with only groundwater as well as groundwater suspensions with aquifer sediment were run as references. It was impossible to adjust pH to the desired level in the experiments with crushed tiles, where also substantial sorption of the test compounds and server clogging of filters used in sampling occurred, and this material was therefore useless as biomass support material. Presence of rock wool supported growth of bacteria and increased the degradation (in terms of rates and number of compounds degraded) compared with experiments with groundwater only. However, the degradation was less and the degradation patterns varied more than in the presence of aquifer sediment. Quartz sand gave the most promising results with respect to growth of bacteria, and the degradation patterns of most of the compounds were similar to those obtained in experiments including aquifer sediments, although the latter showed the most substantial degradation. This study suggests that in case aquifer sediment is not available, quartz sand should be added as biomass support material in studies on degradation of organic xenobiotics in groundwater environments.

Effect of ferrous iron concentration on the catalytic activity of immobilized cells of Thiobacillus ferrooxidans

The kinetics of continuous oxidation of ferrous iron by immobilized cells of Thiobacillus ferrooxidans was studied in a packed-bed bioreactor. Polyurethane foam biomass support particles were used as carriers for cell immobilization. Effects of ferrous iron concentration and its volumetric loading on the kinetics of the reaction were investigated. Media containing different concentrations of ferrous iron in the range 5–20 kg m-3 were tested. For each medium the kinetics of the reaction at different volumetric loadings of ferrous iron, at a constant temperature of 30°C, were determined. With media containing 5 kg m-3 and 10 kg m-3 Fe2+, the fastest oxidation rates of 34.25 kg m-3 h-1 and 32 kg m-3 h-1 were achieved at a dilution rate of around 6 h-1, which represents a residence time of 10 min. Employing a higher concentration of ferrous iron (20 kg m-3) in the medium resulted in lower oxidation rates, with a maximum value of 10 kg m-3 h-1, indicating an inhibitory effect of ferrous iron on growth and activity of T. ferrooxidans. The reliable performance of the bioreactor during the course of the experiments confirmed the suitability of polyurethane foam biomass support particles as carriers for T. ferrooxidans immobilization.

Transesterification of phospholipids by acetone‐dried cells of aRhizopus species immobilized on biomass support particles

AbstractAcetone‐dried cells of aRhizopus species, immobilized on biomass support particles were applied to the transesterification between phosphatidylcholine and heptadecanoic acid. All eight species ofRhizopus tested exhibited good transesterification performance, with the immobilized cells ofR. niveus, R. delemar, andR. javanicus showing particularly high reaction rates which were equal to or exceeded that of a commercially available immobilized lipase preparation, Lipozyme IM60.

Alcoholysis of olive oil for producing wax esters by intracellular lipase in immobilized fungus cells

Alcoholysis of olive oil was carried out with lauryl and palmityl alcohols for producing wax esters. The reaction can be catalyzed efficiently by cell-bound lipase of Rhizopus niveous fungus cells immobilized within cellulose biomass support particles. Influences of reaction conditions such as water content, temperature, and substrate concentrations on reaction rates and yields were investigated.

Growth kinetics of animal cells immobilized within porous support particles in a perfusion culture

The growth kinetics of anchorage-independent animal cells [mouse myeloma MPC-11 (ATCC CCL 167)] immobilized within porous polyvinyl formal resin biomass support particles (BSPs; 3 x 3 x 3 mm cubes; mean pore diameter, 60 microns) was analyzed by measuring intracellular and extracellular lactate dehydrogenase (LDH) activities in a perfusion culture. First, the intracellular LDH content of cells immobilized within the BSPs was assayed in a shake-flask culture and found to remain almost comparable to that of non-immobilized cells in the exponential growth phase under static culture. Then, cells inoculated in the BSPs were grown in a continuous stirred-tank bioreactor. Using the LDH content of non-immobilized cells, the density of immobilized cells and the numbers of leaked and dead cells were evaluated, respectively, by the intracellular LDH activity of immobilized and leaked cells and the LDH activity in cell-free culture supernatant. In the initial period, immobilized cells exhibited exponential growth at a constant apparent specific growth rate; however, the actual specific growth rate, which takes into consideration cell death and cell leakage, decreased significantly. In the stationary phase, the actual specific growth rate maintained a constant but markedly lower value than during exponential growth.

A trickle bed reactor for ferrous sulphate oxidation using Thiobacillus ferrooxidans

A trickle bed reactor was used to improve ferrous sulphate oxidation rate with Thiobacillus ferrooxidans immobilised in BSPs (Biomass Support Particles). A maximum iron(II) oxidation rate of 4.4 gL−1h−1 was observed at a dilution rate D = 0.9 h−1. The ability of the reactor to operate under non-aseptic conditions due to the chemoautotrophy and acidophilia of the bacterium makes industrial application promising.

Anaerobic biodegradation of a petrochemical waste-water using biomass support particles

During the anaerobic biodegradation of effluent from a dimethyl terephthalate (DMT) manufacturing plant, reduction in chemical oxygen demand (COD) degradation and biogas formation was observed after the waste-water concentration exceeded 25% of added feed COD. This condition reverted back to normal after 25–30 days when the DMT waste-water concentration in the feed was brought down to a non-toxic level. However, the above effects were observed only after the concentration of DMT waste-water reached more than 75% of added feed COD when biomass support particles (BSP) were augmented to the system. In the BSP system, a biomass concentration of up to 7000 mg/l was retained and the sludge retention time increased to > 200 days compared to 2200 mg/l and 8–10 days, respectively, in the system without BSP (control). Formaldehyde in the waste-water was found to be responsible for the observed toxicity. The BSP system was found to resist formaldehyde toxicity of up to 375 mg/l as against 125 mg/l in the control system. Moreover, the BSP system recovered from the toxicity much faster (15 days) than the control (25–30 days). The advantages of the BSP system in anaerobic treatment of DMT waste-water are discussed.

Anaerobic biodegradation of a petrochemical waste-water using biomass support particles

Anaerobic biodegradation of a petrochemical waste-water using biomass support particles

Simultaneous Removal of BOD and Nitrogen with Anoxic/Oxic Porous Biomass Support Systems

To protect the public water, there is a growing demand to treat domestic gray water as well as night soil using onsite wastewater treatment systems (OWTS) in Japan. Therefore, to meet this demand, we seek the potential of the technology of the system with porous biomass support particles (BSP) using large number of small, open-cell foam pads to support high concentration of biomass in an aeration tank. From aneconomic point of view, durability of pads is an important factor of this process. Polyurethane foam with certain physical characteristics was chosen for pads. To attain simultaneous removal of BOD and nitrogen in an aeration tank, optimum pore size and pads dimensions were chosen in terms of diffusion. To aim for steady and further removal of nitrogen with biomass both on BSP and in suspension, we applied intermittent anoxic/oxic porous biomass support systems process to a full-scale field test, operated in the manner of 1.5 hours aeration and subsequent 0.5 hours agitation. For 330 days of the experiment, less than 20 mg/L and 15 mg/L of effluent BOD and nitrogen are achieved regardless of water temperature between 13 and 31 degrees centigrade.

Feedforward/feedback control of interesterification of fats and oils using a microaqueous bioreactor

In order to maintain a constant triglyceride composition in the effluent from a microaqueous bioreactor using filamentous fungus immobilized within Biomass Support Particles as a lipase catalyst, a feedforward/feedback controller with an on-line enzyme activity estimator and a state estimation controller based on a linear Kalman Filter were developed. Both simulation and experimental studies proved that the above systems successfully controlled the glyceride composition of the continuous interesterification reaction of fats and oils.

Growth and death behaviour of anchorage-independent animal cells immobilized within porous support matrices.

Growth and death of anchorage-independent animal cells entrapped within porous biomass support particles (BSPs) in static or shake-flask cultures were evaluated by comparison of enzyme activity with non-immobilized cells grown under static culture using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and release of lactate dehydrogenase into the culture medium. Mouse myeloma MPC-11 (ATCC CCL 167) cells inoculated within porous polyvinyl formal resin BSPs (3 x 3 x 3 or 2 x 2 x 2 mm; mean pore diameter, 60 microns) grew exponentially at a specific growth rate comparable to that of non-immobilized cells in the initial period of incubation. Entrapped cells then reached the stationary phase with a cell density over 10(7) cells/cm3 BSP. The death rate of entrapped cells increased in response to the rise in viable cell density in the BSPs. Observation of viable cell distribution within the BSPs using MTT staining indicated that the cells concentrated within a thin outer shell of the BSPs with time. After the immobilized cells reached the stationary phase, penetration of cells into the outer shell ceased and heterogeneous distribution of cell density occurred in the viable cell layer in the shake-flask culture.

Enzymatic hydrolysis of triglycerides byRhizopus delemarimmobilized on biomass support particles

Abstract The best medium composition for production of intracellular Iipase by Rhizopus delemar contained oleic acid and no glucose. The technique of cell immobilization using polyurethane foam biomass support particles was studied as a means of further enhancing intracellular lipase activity. Fungal mycelia were found to strongly adhere to the polyurethane foam matrix during growth to form immobilized cell biocataiysts, which, after cell membrane permeabiiization and drying, exhibited a Iipase activity 3.3 times greater than that of cells grown in a freely suspended state. Upase within the Immobilized cells showed properties similar to purified extracellular Rhizopus delemar lipase but was more thermostable than the free enzyme. The biocatalyst was used for triglyceride hydrolysis in a continuous stirred‐tank reactor. In this format it was found that the degree of hydrolysis of olive oil and the flavor profile of lipolyzed milk fat could be easily controlled.

Long-term cultivation of anchorage-independent animal cells immobilized within reticulated biomass support particles in a circulating bed fermentor.

Long-term cultivation of anchorage-independent animal cells immobilized within porous biomass support particles (BSPs) using a gas-stirred circulating bed fermentor (CBF) was investigated. Inoculation of mouse myeloma MPC-11 (ATCC CCL 167) cells into reticulated polyvinyl formal resin BSPs (3 x 3 x 3 mm; mean pore diameter, 60 microns; porosity, 0.88) and the repeated batch culture of inoculated cells were performed under gentle circulation of BSPs, induced by sparging air from the base of the fermentor. The glucose uptake rate of cells decreased in the initial period just after the start of circulation, since a relatively large number of cells leaked from the BSPs. After that period, the uptake rate gradually increased and the leakage of cells diminished. In the meantime, when inoculated cells were incubated statically by introducing air into days before circulating the BSPs, glucose consumption became very rapid and cell density in the BSPs reached at least 10(7) cells/cm3 BSP. Thus, a long-term cultivation without significant leakage of cells and with high cell density in BSPs was successfully achieved in the CBF-BSP system.

Continuous interesterification of oils and fats using dried fungus immobilized in biomass support particles

The industrial feasibility of an interesterification process using acetone-dried fungus (as a lipase catalyst) immobilized in biomass support particles (BSPs) was examined by continuous interesterification between olive oil and methyl stearate, where the water content of the reaction mixture ( C w) was controlled at a given value. The C w affected not only the inactivation rate of lipase in the cells but also the production rate of the by-product (diglycerides). The optimal C w was determined as about 100 ppm. The half-life of lipase in the cells was about 1200 h at the optimal C w, suggesting that the interesterification process using the immobilized fungus is industrially feasible.

The uptake of copper from aqueous solution by immobilized fungal biomass

AbstractThe removal of cupric ions from aqueous solution by a biosorption column in which the Rhizopus arrhizus fungal biomass was immobilized in reticulated foam biomass support particles was studied. Solution pH was found to be crucial to copper uptake, with the optimum range being 6·7–7·0. The removal efficiency was usually higher at low influent copper concentration and long residence time. The presence of other cations and anions inhibited copper uptake in the following order: for the cations, Mn2+ ≫ Zn2+ > Cd2+ > Mg2+ > Ca2+; for the anions, EDTA ≫ SO ≫ Cl−. The biosorption process was fully reversible and regenerated columns showed undiminished performance.

Effects of aeration rate on intracellular lipase production by Rhizopus chinensis immobilized within biomass support particles in a circulating bed fermentor

The effects of the aeration rate on intracellular lipase production by Rhizopus chinensis immobilized in biomass support particles (BSPs) was examined using circulating bed fermentors (CBFs) of three sizes. The minimum aeration rate that achieved good circulation of BSPs in CBF was appropriate for BSPs-CBF intracellular lipase production.

Cell aggregation as a trigger for enhancement of intracellular lipase production by a Rhizopus species

Immobilization of Rhizopus chinensis cells in various Biomass support particles (BSPs) made from polyurethane, nylon, polyester, stainless steel, polyvinyl alcohol, and cellulose enhanced intracellular lipase activity as much as several-fold that of freely suspended cells irrespective of the BSP material. In freely suspended cultivation the overall intracellular lipase activity of free cells, consisting of pellet cells and pulp-like cells, increased with an increase in the ratio of pellet cells to pulp-like cells. It was thus considered that cell aggregation seems to be a principal factor in the enhancement of intracellular lipase formation by Rh. chinensis. Also, other Rhizopus species such as Rh. javanicus, Rh. delemar, Rh. oligosporus, Rh. niveus, Rh. japonicus and Rh. oryzae were immobilized in both polyurethane and cellulose BSPs, In all species used, intracellular lipase production was significantly enhanced compared to results without immobilization. Cell aggregation therefore seems to be a common trigger for the enhancement of intracellular lipase production by Rhizopus species.

Sulphur and sulphate reduction with acetate and propionate in an aerobic process for sulphide removal

Sulphide production rates of sulphur-and sulphate-reducing bacteria up to 50 mg per biomass support particle per day were observed in an aerated sulphide-removal reactor with polyurethane (PUR) foam as carrier material. The optimal pH and temperature for the sulphide-producing bacteria were 8.0 and 30°C respectively. Raschig rings and four types of cube-shaped PUR particles were tested as carrier materials. When using PUR particles, the sulphide production rate was always between 3% and 4% of the sulphide removal rate, dependent on the dimensions and pore size of the polyurethane support particles. With the Raschig rings this ratio was only 2% and for reactors in which no carrier materials were present it was even lower (0.6%). Media containing different mixtures of acetate, propionate, sulphur and sulphate inoculated under anoxic conditions with sludge from the aerated reactor showed the presence of acetate-degrading sulphur-reducing, but not of acetate-degrading sulphate-reducing, bacteria. With propionate as sole electron donor no degradation occurred in the presence of sulphur within 2 weeks, whereas sulphate-dependent propionate oxidation started after 5–6 days incubation. Bacteria were isolated and resembled Desulfuromonas acetoxidans and Desulfobulbus propionicus morphologically and physiologically.

Immobilisation of anchorage-independent animal cells using reticulated polyvinyl formal resin biomass support particles

Immobilisation of anchorage-independent animal cells using Biomas Support Particles (BSPs) was investigated. Mouse myeloma MPC-11 cells were physically entrapped in three-dimensional reticulated polyvinyl formal (PVF) resin PSPs (3×3×3 mm) with matrices of relatively small pores (30–100 μm) by filtering medium containing cells or incubating in a shake flask for inoculation. Physically entrapped cells became immobilised in the BSPs by forming aggregates within the matrices of the reticulated PVF resin, and cell density in the BSPs reached at least 107 cells/cm3 BSP. Immobilised cells in the BSPs were successfully cultivated in static and/or shake-flask cultures with regular replacement of medium for a long period.