Microorganisms immobilized

Biocol A process for removing dyes from aqueous effluents using a microorganism immobilized on activated carbon. The microorganism, Schewanella putrifaciens, was first isolated and characterized at the University of Leeds. The process was developed in Queens University, Belfast, in conjunction with British Textile Technology Group. Piloted from April 2001 at a dyeworks in County Antrim. 

In spite of large soil stores of organic matter and plant nutrients, net primary production within almost all arctic ecosystem types is limited by low availability of plant-available nutrients, particularly N, and of P in wet ecosystem types. This is due to slow microbial mineralization rates associated with low temperature and often combined with extreme wet or dry conditions in several ecosystem types. Furthermore, soil microorganisms immobilize nutrients and may even act as competitors with the plants for nutrients during the growing season, when the nutrient demand by both microbes and plants is high. Recent research has, however, shown that plants can partially circumvent possible competition... 

Industrial microbiology—Congresses. 2. Microorganisms, Immobilized—Congresses. 3. Micro-organisms, Immobilized—Industrial applications—Con-... 

Cunningham CJ, Ivshina IB, Lozinsky VI, Kuyukina MS, Philp JC (2004) Bior ediation of diesel-contaminated soil by microorganisms immobilized in polyvinyl alcohol. Int Biodeter Biodegr 54 167-174... 

Cohen, Y. (2001) Biofiltration - the treatment of fluids by microorganisms immobilized into the filter bedding material a review. Bioresource Technology, 77, 257-274. 

One of the maj or problems with microorganism immobilization is the hmitation of mass transfer, particularly the depletion of oxygen inside the immobilization matrices. Because of the severe oxygenation problem, immobilization technology has been mainly confined to anaerobic processes in which either obhgate anaerobes are employed or only the anaerobic components of the facultative metabolic mechanisms are selectively utilized. 

The products of electrochemical pretreatment of 1 were oxidized in a biosorber by microorganisms immobilized on activated carbon. Arsenic salts after EC may be used as a secondary raw material. 

Analyte Microorganism Immobilization technique Transducer Response time Linearity Reference... 

Another assay of bioactivity sensors exploits microorganisms immobilized oti electrode surfaces and monitors their activity in dependence on the surrounding conditions. ... 

Arsenic is another element with different bioavailabiUty in its different redox states. Arsenic is not known to be an essential nutrient for eukaryotes, but arsenate (As(V)) and arsenite (As(III)) are toxic, with the latter being rather more so, at least to mammals. Nevertheless, some microorganisms grow at the expense of reducing arsenate to arsenite (81), while others are able to reduce these species to more reduced forms. In this case it is known that the element can be immobilized as an insoluble polymetallic sulfide by sulfate reducing bacteria, presumably adventitiously due to the production of hydrogen sulfide (82). Indeed many contaminant metal and metalloid ions can be immobilized as metal sulfides by sulfate reducing bacteria. 

Biosynthesis ofS(— )-M llc Acid. Aqueous fumaric acid is converted to levorotatory malic acid by the intracellular enzyme, fumarase, which is produced by various microorganisms. A Japanese process for continuous commercial production of S(—)-mahc acid from fumaric acid is based on the use of immobilized Brevibacteriumflavum cells in carrageenan (32). The yield of pyrogen-free S(—)-mahc acid that is suitable for pharmaceutical use is ca 70% of the theoretical. 

Immobilized system the air circulates over a film of microorganisms that grows on a solid surface. In an immobilized bioreactor, particulate biocatalysts for enzyme production and conversion of penicillin to 6-aminopenicillanic acid are used. 

Endosulfan is released to the environment mainly as the result of its use as an insecticide. Significant contamination is limited to areas where endosulfan is manufactured, formulated, applied, or disposed of. The compound partitions to the atmosphere and to soils and sediments. Endosulfan can be transported over long distances in the atmosphere, but the compound is relatively immobile in soils. It is transformed by hydrolysis to the diol and by microorganisms to a number of different metabolites. It is bioconcentrated only to low levels and does not biomagnify in terrestrial or aquatic food chains. 

For most applications, enzymes are purified after isolation from various types of organisms and microorganisms. Unfortunately, for process application, they are then usually quite unstable and highly sensitive to reaction conditions, which results in their short operational hfetimes. Moreover, while used in chemical transformations performed in water, most enzymes operate under homogeneous catalysis conditions and, as a rule, cannot be recovered in the active form from reaction mixtures for reuse. A common approach to overcome these limitations is based on immobilization of enzymes on solid supports. As a result of such an operation, heterogeneous biocatalysts, both for the aqueous and nonaqueous procedures, are obtained. 

Some of the industrial biocatalysts are nitrile hydralase (Nitto Chemicals), which has a productivity of 50 g acrylamide per litre per hour penicillin G amidase (Smith Kline Beechem and others), which has a productivity of 1 - 2 tonnes 6-APA per kg of the immobilized enzyme glucose isomerase (Novo Nordisk, etc.), which has a productivity of 20 tonnes of high fmctose syrup per kg of immobilized enzyme (Cheetham, 1998). Wandrey et al. (2000) have given an account of industrial biocatalysis past, present, and future. It appears that more than 100 different biotransformations are carried out in industry. In the case of isolated enzymes the cost of enzyme is expected to drop due to an efficient production with genetically engineered microorganisms or higher cells. Rozzell (1999) has discussed myths and realities... 

All soil metabolic proce.sses are driven by enzymes. The main sources of enzymes in soil are roots, animals, and microorganisms the last are considered to be the most important (49). Once enzymes are produced and excreted from microbial cells or from root cells, they face harsh conditions most may be rapidly decomposed by organisms (50), part may be adsorbed onto soil organomineral colloids and possibly protected against microbial degradation (51), and a minor portion may stand active in soil solution (52). The fraction of extracellular enzyme activity of soil, which is not denaturated and/or inactivated through interactions with soil fabric (51), is called naturally stabilized or immobilized. Moreover, it has been hypothesized that immobilized enzymes have a peculiar behavior, for they might not require cofactors for their catalysis. 

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