Biodegradation processes

Zwank L, M Berg, M Eisner, TC Schmidt, RP Schwarzenbach, SB Haderlien (2005) New evaluation scheme for two-dimensional isotope analysis to decipher biodegradation processes application to groundwater contamination by MTBE. Environ Sci Technol 39 1018-1029. 

On the other hand, we need to ensure that stronger sanitisers do not damage the health of workers during discharge of toilet tanks nor upset normal biodegradation processes in effluent treatment plants. 

Several qualitative models for biodegradation in the deep-well environment have been suggested. They do not allow quantitative predictions to be made, but they do provide insight into the types of biodegradation processes that may occur. These models have not been expressed quantitatively to... 

Biological Activity Evolution Profile Through the Biodegradation Process. 236... 

Dioxin-like activity during biodegradation processes of BP3, BP1 and 4-MBC by T. versicolor was below detection limits for all three compounds. These data indicate that metabolites produced by T. versicolor were in small amounts or rapidly metabolized in non-dioxin-like compounds. 

Ong SA, Toorisaka E, Hirata M et al (2008) Combination of adsorption and biodegradation processes for textile effluent treatment using a granular activated carbon-biofilm configured packed column system. J Environ Sci 20 952-956... 

The ambient temperature and the possible use of solar UV are the advantages of photocatalysis moreover, Ti02 is not toxic. The reaction mechanisms of Ti02 photocatalytic oxidation of azo dyes was similar to the biodegradation process of oxidation of azo dyes with OH radical. 

The acquisition and assimilation of bioelements are the most fundamental processes in an organism s struggle for life. It is therefore obvious that in complex natural systems the competition between thousands of species for limited quantities of a small number of elements is a major evolutionary factor. However, the individual contributions of the physical and biochemical aspects of nutrition to the fitness of an organism are widely unknown. The frequent observation that biodegradation processes, e.g. in soil remediation, are limited by physical obstacles to substrate acquisition, rather than by biochemical incapacities, points at the importance of substrate mobilisation strategies. 

Adsorption onto biomass, eventually followed by an aerobic or anaerobic biodegradation process. 

While 02 serves as the electron acceptor in aerobic biodegradation processes forming H20 as the final product, degradation in anaerobic systems depends on alternative electron acceptors such as sulfate, nitrate or carbonate, which yield, ultimately, hydrogen sulfide (H2S), molecular nitrogen (N2) and/or ammonia (NH3) and methane (CH4), respectively. 

Generally, LAS biodegradation processes were previously monitored either as primary biodegradation (a decreasing LAS concentration) or as mineralisation (formation of biomass and/or C02). Both processes have usually been fitted to a first order kinetics, but this approximation is only valid if there has been no prior acclimatisation phase an initial lag phase is usually present in biodegradation tests [4]. Nevertheless, first order kinetic constants may be used for special cases or for a preliminary characterisation of the process. 

However, precise fits require the use of at least second order models, which include three characteristic phases in the biodegradation process [4] (i) an acclimatisation or lag phase (ii) an exponential phase with most of the effective degradation and (iii) a final phase in which the microorganism population is stable and some portion of the substrate could persist (see Fig. 5.3.1(a) [21]). 

The presence of suspended solid materials increases the extent of LAS biodegradation [13,28], but the rate of the process remains invariable. The influence of the particulate material is due specifically to the increased density of the microbiota associated with sediments. However, suspended solids may also reduce the bioavailability of IAS as a result of its sorption onto preferential sites (e.g. clays, humic acids), although this is a secondary effect due to the reversibility of the sorption process. Salinity does not affect IAS degradation directly, but could also reduce LAS bioavailability by reducing the solubility of this molecule [5], Another relevant factor to be taken into account is that biodegradation processes in the marine environment could be limited by the concentration of nutrients, especially of phosphorus and nitrogen [34],... 

The removal of LAS from the marine medium is, in general, a slow, but efficient process. co-Oxidation is the first step in the LAS biodegradation process, resulting in SPCs. (3-Oxidation is the main route responsible for... 

---