Monitoring of Phenol in Wastewater Bioremediation by HPLC

Bioremediation emphasizes the detoxification and destruction of toxic substances by microorganisms. Wastewater obtained from an industrial concern was solvent extracted with methyl alcohol and dichloromethane and analysed by GC/MS. Besides phenol, a large variety of organic compounds were detected. Under controlled laboratory conditions, the wastewater was innoculated with a mixed culture of microorganisms specially selected for their abilities to degrade phenol. Samples were collected at regular intervals from the stirred tank bioreactor and analysed for phenol by reverse phase HPLC with a C18 column. Results shows that from an initial phenol concentration of 987 ppm, slightly more than 50% was destroyed within 163 hours. The dry weight of the microorganisms and the plate count (CFU/ml) shows a steady increase from 0.5238 gms to 0.5355 gms and from 1.1E+9 to 1.94E+13 respectively over the same period. This suggested that the phenol was consumed by the microorganisms as the sole carbon source.     

Processing and Morphology Impacts on Mechanical Properties of Fungal Based Biopolymer Composites

Fungal based biopolymer matrix composites with lignocellulosic agricultural waste as the filler are a viable alternative for some applications of synthetic polymers. This research provides insight into the impact of the processing method and composition of agriwaste/fungal biopolymer composites on structure and mechanical properties. The impact of nutrition during inoculation and after a homogenization step on the three-point bend flexural modulus and strength was determined. Increasing supplemental nutrition at inoculation had little effect on the overall composite strength or modulus; however, increasing carbohydrate loading after a homogenization step increased flexural stress at yield and bulk flexural modulus. The contiguity of the network formed was notably higher in the latter scenario, suggesting that the increase in modulus and strength of the final composite after homogenization was the result of contiguous hyphal network formation, which improves the integrity of the matrix and the ability to transfer load to the filler particles.     

Environmental hazard profile of organic chemicals: An experimental method for the assessment of the behaviour of organic chemicals in the ecosphere by means of simple laboratory tests with 14C labelled chemicals

The concept of “Environmental Hazard Profile” developed at this institute has been tested with 100 ¹⁴C-labelled organic compounds. Concentration factors in activated sludge, in algae and fish were determined. The microbial degradation of the chemicals to CO₂ in activated sludge and the decomposition to CO₂ under artificial light were determined. Ranking of compounds is given in the order of falling concentration factors and accumulation in rats respectively, and decreasing rates of decomposition. Relationship between chemical structure and accumulative and degradative behaviours is demonstrated using some selected groups of chemicals, such as benzenes, phenols, biphenyls and polyaromatic hydrocarbons. Correlations between the octanol/water partition coefficient, concentration factors and rates of decomposition could be established. Evaluation of test compounds was possible using hazard profiles obtained by the sum of single test results.     

Verhalten von 2,4-Dichlorphenol, 2,4,6-Trichlorphenol und Pentachlorphenol bei der Kompostierung in einer standardisierten Laboranlage

In einer Versuchsanlage im Labormaßstab zur Kompostierung von standardisierten Hausmüll wurden Translokation, Umwandlung und Abbau von ¹⁴C-markierten 2,4-Dichlorphenol, 2,4,6-Trichlorphenol und Pentachlorphenol untersucht. Als Hauptabbauprodukte wurden die entsprechenden Anisole gefunden. Die Bilanzierung zeigt, daß das hoch chlorierte Pentachlorphenol mit der höchsten Konzentration im Kompost verbleibt.     

Biotic homogenization and differentiation of plant communities in tropical and subtropical forests

Anthropogenic impacts on biodiversity can lead to biotic homogenization (BH) and biotic differentiation (BD). BH is a process of increasing similarity in community composition (including taxonomic, functional, and phylogenetic components), whereas BD is a process of decreasing similarity over space and time. Here, we conducted a systematic review of BH and BD in plant communities in tropical and subtropical forests to identify trends and knowledge gaps. Our bibliometric search in the Web of Science returned 1989 papers, of which 151 matched our criteria and were included in the analysis. The Neotropical region had the largest number of articles, and Brazil was the most represented country with 92 studies. Regarding the type of change, homogenization was more frequent than differentiation (noted in 69.6% of publications). The taxonomic diversity component was measured more often than functional and phylogenetic diversity components. Most studies (75.6%) assessed homogenization and differentiation based on a single observation in time; as opposed to few studies that monitored plant community over multiple years. Forest fragmentation was cited as the main determinant of homogenization and differentiation processes (57.2% of articles). Our results highlight the importance of evaluating community composition over time and more than taxonomic components (i.e., functional and phylogenetic) to advance understanding of homogenization and differentiation. Both processes were scale dependent and not mutually exclusive. As such, future research should consider differentiation as a potential transition phase to homogenization and that potential differences in both processes may depend on the spatial and temporal scale adopted. Understanding the complexity and causes of homogenization and differentiation is essential for biodiversity conservation in a world increasingly affected by anthropogenic disturbances.