Biomass immobilization

Amazon terra firme forests are lower than those measured on richer soUs in Costa Rica and Barro Colorado, Panama. In general all the organic N mineralized is subsequently nitrified, leaving little or no free NH4. Under natural conditions, however, NH4 could be incorporated into biomass, immobilized in the soil, or taken up by the vegetation, resulting in a reduction of nitrification rates. 

Navratil M., Domeny Z., Hronsky V., Stuidic E., Smogrovicova D. and Gemeiner P. Use of biolumi-nometry for determination of active yeast biomass immobilized in ionotropic hydrogels. Analytical Biochemistry 284 (2) (2000) 394-400. 

Carbon source Biomass immobilized in 10 ml, g Volatile acids, pmol/100 ml Pyruvic acid, pmol/100 ml... 

Water often is treated in simple vessels known as batch reactors, which hold from a few hundred to many thousands of liters. Nutrients, microorganism, or both may be added to promote degradation of particular contaminants. Another variation on reactors designed for treatment of water is the fluidized bed. Fluidized beds usually contain biomass immobilized on or within carriers (e.g., polysaccharide-based beads, plastic saddles, sand particles, etc.). These carrier matrixes are circulated... 

Like enzymes, whole cells are sometime immobilized by attachment to a surface or by entrapment within a carrier material. One motivation for this is similar to the motivation for using biomass recycle in a continuous process. The cells are grown under optimal conditions for cell growth but are used at conditions optimized for transformation of substrate. A great variety of reactor types have been proposed including packed beds, fluidized and spouted beds, and air-lift reactors. A semicommercial process for beer used an air-lift reactor to achieve reaction times of 1 day compared with 5-7 days for the normal batch process. Unfortunately, the beer suffered from a mismatched flavour profile that was attributed to mass transfer limitations. 

Immobilization is the technique of choice in many food industry processes and especially in beverage production. Many immobilization technologies have already been tested and some are applied in the production of beer, wine, vinegar, and other food products using a traditional approach with cultme adhesion (i.e., Acetobacter in vinegar production) or more modem approaches with entrapment of yeast biomass (i.e., sparkling wines, cheeses, and yogurts). 

Combining ammonium immobilization rates with estimates of C inputs and C maintenance requirement (proportional to the active microbial biomass), whose difference gave C available for microbial growth from the same experimental system (111,128), it allowed the building up of a conceptual model for C and N... 

Therefore if the carbon substrate is present at sufficiently high concentration anywhere in the rhizosphere (i.e., p p, ax), the microbial biomass will increase exponentially. Most models have considered the microbes to be immobile and so Eq. (33) can be solved independently for each position in the rhizosphere provided the substrate concentration is known. This, in turn, is simulated by treating substrate-carbon as the diffusing solute in Eq. (32). The substrate consumption by microorganisms is considered as a sink term in the diffusion equation, Eq. (8). 

CST, continuous stirred tank EGSB, expanded granular sludge blanket HAIB, horizontal-flow anaerobic immobilized biomass. 

More specifically, the invention involves the use of Thiobacillus denitrificans under anaerobic conditions to oxidize sulfur compounds such as hydrogen sulfide to sulfate. The process may be carried out in various ways such as in a batch or a continuous bioreactor system using a suspended or an immobilized biocatalyst. The method is particularly applicable to treating natural gas containing hydrogen sulfide and producing a biomass byproduct. 

Improvement of intraparticle mass transfer is the goal of some particle research efforts. One novel approach that has been recently tested is the co-immobilization of algae with bacteria the algae produced oxygen and the bacteria produced the desired product (Chevalier and de la Noue, 1988). Another method used microporous particles entrapped within alginate bead bioparticles to prevent excess biomass growth that could hinder intraparticle mass transfer (Seki et al., 1993). 

A continuous centrifugal bioreactor, in which cells are fluidized in balance with centrifugal forces, has been designed to allow high density cell cultivation and superior aeration without elutriation of the suspended cells (van Wie et al., 1991). Reactor performance was hampered by elutriation of biomass by evolved gas in an anaerobic fermentation, indicating that it may not be suitable in its present state for three-phase fermentations. Immobilization of the cells on denser particles may overcome this problem. 

Lebeau et al. (2002) investigated the sorption of cadmium by viable microbial cells that were free or immobilized in alginate beads by incubating the bacteria in a liquid soil extract medium at pH 5 7 and Cd concentrations of 1 to 10 mg L-1. The percentage of Cd biosorbed reached a maximum (69%) at low Cd concentrations and neutral pH. Thus, the effectiveness of bacteria, inoculated into metal-contaminated soils, would largely depend on the concentration of the metal and its distribution between the biomass and the medium. 

Ladd JN, Amato M, Parsons JW (1977) Studies of nitrogen immobilization and mineralization in calcareous soils. 111. Concentration and distribution of nitrogen derived from soil biomass. In Soil organic matter studies, vol 1. International Atomic Energy Agency, Vienna, pp 301-311... 

Bioavailability of Metals, Nonmetals and Xenobiotics Immobilized on Soil Components, (4) Distribution and Activity of Biomolecules in Terrestrial Systems, (5) Interactions between Soil Microbial Biomass and Organic Matter/Nutrient Transformations, and (6) Impact of Interactions among Soil Mineral Colloids, Organic Matter and Biota on Risk Assessment and Restoration of Terrestrial Ecosystems. There were 2 plenary lectures, 9 invited speakers, 36 oral presentations and 45 posters. Dr. N. Senesi from University of Bari, Italy, presented an IUPAC lecture entitled Metal-Humic... 

Resmi et al. [59] used laterite stones for the immobilization of Pseudomonas putida (MTCC 1194). The amount of bacterial biomass attached to the support was 8.64 g/100 g of stones on dry weight basis. Packed bed reactor was used for treating mixture of seven azo dyes. With the help of immobilized bacterial strain, dye mixture was degraded to nontoxic smaller molecules. It was reported that even after 2 months, bacteria-coated pebbles were stable and suitable for the aerobic degradation of azo dyes. With the help of TLC and HPLC, 61.7% degradation was reported at the concentration of 50 pg/mL of dye. 

For effective biological treatment of dye wastewater, immobilization of bacteria under aerobic anaerobic high-rate reactors should be given special attention. The main cause of effective treatment of these xenobiotics under immobilized condition in high rate reactors is the rapid facile reduction of these compounds to products of lower toxicity [68, 69]. Moreover, the immobilization of anaerobic bacteria and maintenance of a high concentration of biomass in the high rate reactors are factors that improve the tolerance of the anaerobic system to toxic substances [70, 71]. 

The bioconversion process of Acid Orange 7 will be hereby analyzed. This is an incremental study with respect to that due to Lodato et al. [41], based on the operation of an airlift reactor with cells of Pseudomonas sp. 0X1 immobilized on natural pumice (density = 1,000 kg/m3 particle size = 800-1,000 pm). Details regarding the strain, medium, culture growth and main diagnostics of the liquid phase are reported by Lodato et al. [41]. Elemental analysis of dry biomass was obtained by a C/H/N 600 LECO analyzer. 

Tests were carried out at 25°C and at initial pH 6.9. Cultures in the liquid medium were incubated in 50 mL Falcon tubes, continuously shaked at 220 rpm. Each culture contained a fresh Pseudomonas sp. 0X1 colony in 10 mL of medium. The airlift with 10 g of pumice was sterilized at 121°C for 30 min and then housed in a sterile room. One-day culture was transferred to the reactor and, after a batch phase, liquid medium with phenol as the only carbon source was continuously fed. The reactor volume V was fixed at 0.13 L. Aerobic conditions were established sparging technical air. Under these conditions microorganism started to grow immobilized on the solid s support. When immobilized biomass approached steady state, cyclic operation of the airlift was started by alternating aerobic/anaerobic conditions. 

Immobilized biomass 3ssXiLf VL-KAXLVL K03Lt/RfssX+nx- Krh+ 2/Ki 3Lt/RfssX (T.3.4)... 

Adhesion of suspended cell to the bioparticles was modeled through a first-order kinetics with respect to suspended biomass [58, 65], Gjaltema et al. [66, 67] reported that specific detachment rate in airlift was mainly due to the particle-to-particle collisions. Accordingly, it was assumed that the detachment rate was proportional to the immobilized biomass concentration. 

Decolorization of azo dye R016 by immobilized cultures of I. lacteus was compared in three different reactor systems [59]. Different size of PuF was used for immobilization in reactors. Biomass concentration was reported to be 11.6, 8.3, and 4.9 g dw/L in Small Trickle Bed Reactor (STBR), Large Trickle Bed Reactor, and Rotating Disk Bioreactor, respectively. Decolorization rate was found high in STBR, where 90% decolorization rates were achieved after 3 days. Dye decolorization was highly efficient, but no direct relationship between the extracellular enzyme activities (laccase and MnP) and dye decolorization capacity was found. 

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