Summary: B urkholderia fungorum FLU 100 simultaneously oxidized any mixture of toluene, benzene and mono‐halogen benzenes to (3‐substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3‐methylcatechol, 4‐carboxymethyl‐2‐methylbut‐2‐en‐4‐olide (2‐methyl‐2‐enelactone, 2‐ ML ) accumulated transiently, being further mineralized only after a lag phase of 2 h in case of cells pre‐grown on benzene or mono‐halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono‐halogen benzenes were unable to metabolize 2‐ ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2‐ ML as a substrate. This means that 2‐ ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4‐methylcatechol as a very minor by‐product of toluene degradation in strain FLU 100 resulted in the accumulation of 4‐carboxymethyl‐4‐methylbut‐2‐en‐4‐olide (4‐methyl‐2‐enelactone, 4‐ ML ) as a dead‐end product, excluding its nature as a possible intermediate. Thus, 3‐methylcyclohexa‐3,5‐diene‐1,2‐diol, 3‐methylcatechol, 2‐methyl muconate and 2‐ ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B . fungorum FLU 100.

International contracts to restrict emissions of climate-relevant gases, and thus global warming, also require a critical reconsideration of technologies for treating municipal, commercial, industrial, and agricultural waste gas emissions. A change from energy- and resource-intensive technologies, such as thermal post-combustion and adsorption, as well to low-emission technologies with high energy and resource efficiency, becomes mandatory. Biological processes already meet these requirements, but show restrictions in case of treatment of complex volatile organic compound (VOC) mixtures and space demand. Innovative approaches combining advanced oxidation and biofiltration processes seem to be a solution. In this review, biological processes, both as stand-alone technology and in combination with advanced oxidation processes, were critically evaluated in regard to technical, economical, and climate policy aspects, as well as present limitations and corresponding solutions to overcome these restrictions.

Polybrominated diphenyl ethers (PBDEs) have widely been used for decades as flame retardants in a variety of products like plastics for building insulation, upholstered furniture, electrical appliances, vehicles, aircrafts, polyurethane foams, textiles, cable insulation, appliance plugs and various technical plastics in concentrations of 5–30%. However, PBDEs also act as endocrine disrupters, neurotoxins, and negatively affect fertility. In 2001, worldwide consumption of technically relevant penta-BDEs was still estimated at 7500 tons, octa-BDEs at 3790 tons, and deca-BDE at 56,100 tons, but 50–60% of this total volume are discharged into the environment via sewage sludge and its agricultural use alone. In addition, soils are ubiquitously contaminated by the gaseous or particle-bound transport of PBDEs, which today has its main source in highly contaminated electronic waste recycling sites. The emitted PBDEs enter the food chain via uptake by the plants’ roots and shoots. However, uptake and intrinsic transport behaviour strongly depend on crop specifics and various soil parameters. The relevant exposure and transformation pathways, transport-relevant soil and plant characteristics and both root concentration factors (RCF) and transfer factors (TF) as derivable parameters are addressed and quantified in this review. Finally, a simple predictive model for quantification of RCF and TF based on log K_OW values and the organic content of the soil/lipid content of the plants is also presented.