Effects of the Feeding Solution Composition on a Reductive/Oxidative Sequential Bioelectrochemical Process for Perchloroethylene Removal

Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants due to their improper use in several industrial activities. Specialized microorganisms are able to perform the reductive dechlorination (RD) of high-chlorinated CAHs such as perchloroethylene (PCE), while the low-chlorinated ethenes such as vinyl chloride (VC) are more susceptible to oxidative mechanisms performed by aerobic dechlorinating microorganisms. Bioelectrochemical systems can be used as an effective strategy for the stimulation of both anaerobic and aerobic microbial dechlorination, i.e., a biocathode can be used as an electron donor to perform the RD, while a bioanode can provide the oxygen necessary for the aerobic dechlorination reaction. In this study, a sequential bioelectrochemical process constituted by two membrane-less microbial electrolysis cells connected in series has been, for the first time, operated with synthetic groundwater, also containing sulphate and nitrate, to simulate more realistic process conditions due to the possible establishment of competitive processes for the reducing power, with respect to previous research made with a PCE-contaminated mineral medium (with neither sulphate nor nitrate). The shift from mineral medium to synthetic groundwater showed the establishment of sulphate and nitrate reduction and caused the temporary decrease of the PCE removal efficiency from 100% to 85%. The analysis of the RD biomarkers (i.e., Dehalococcoides mccartyi 16S rRNA and tceA, bvcA, vcrA genes) confirmed the decrement of reductive dechlorination performances after the introduction of the synthetic groundwater, also characterized by a lower ionic strength and nutrients content. On the other hand, the system self-adapted the flowing current to the increased demand for the sulphate and nitrate reduction, so that reducing power was not in defect for the RD, although RD coulombic efficiency was less.

The Influence of Lipids on the Natural Biodiversity of Cultivated Aboriginal Microflora of Urban Soils

Urban soils are subject to significant anthropogenic impact, which affects the physicochemical composition of soils, as well as microbial natural diversity. Anthropogenic pollution of urban soils with lipids, in particular vegetable and mineral oils, can pose a certain danger to the biological balance in the soil ecosystem. For the quantitative determination of the number of heterotrophic microorganisms, MPA, a mineral medium with oil, was used for the isolation of lipolytic bacteria. In the first two weeks after the addition of lipids, a decrease was observed in relation to the control of the number of heterotrophic microorganisms in all variants of the experiment. The negative effect of lipid contamination on the native soil microbiota was short-lived, and by the fourth week of the experiment, a sharp increase in heterotrophic microorganisms was noted. Twenty six strains of bacteria were isolated from the mineral medium with oil. Nine strains were identified that predominated in their numbers over the rest of the bacteria in this environment. Six strains were identified as belonging to the order Enterobacterales, two strains belonged to the order Pseudomonadales, genus Pseudomonas, and one strain belonged to Rhizobium radiobacter.

Biodegradation of the pyrethroid pesticide cyfluthrin by the halophilic bacterium Photobacterium ganghwense isolated from coral reef ecosystem

A halophilic bacterial strain T14 isolated from the mucus of coral Acropora sp. was found to be highly effective in degrading the pyrethroid pesticide, cyfluthrin. T14 was identified as Photobacterium ganghwense (GenBank Accession No. MT360254) based on phenotypic and biochemical characteristics as well as by 16S rRNA gene sequence analysis. The pyrethroid degrading efficiency of P. ganghwense T14 strain was examined under different culture conditions. It was observed that P. ganghwense T14 was able to utilise cyfluthrin as a sole carbon source and was found to grow on mineral medium with pesticide concentrations ranging from 10 to 100 mg l-1. Optimal temperature and pH conditions for efficient cyfluthrin degradation by P. ganghwense T14 were determined as 30° C and 8 respectively. Degradation of cyfluthrin by P. ganghwense T14 was quantitated by gas chromatography-tandem mass spectrometry (GC-MS/MS). Mineral medium supplemented with 100 mg l-1 cyfluthrin and inoculated with P. ganghwense T14 (106 cells ml-1) recorded 92.13% pesticide decomposition within 120 h. Cytotoxicity assay on a fish cell line EM4SpEx derived from the grouper Epinephelus malabaricus, revealed a drastic reduction in cyfluthrin toxicity as evidenced by reduction in the intensity of cell destruction as well as morphological changes when exposed to P. ganghwense T14 treated filtrate, in comparison with that of parent cyfluthrin filtrate. Results of the study clearly indicated potential bioremediative use of P. ganghwense T14 in cyfluthrin contaminated sites.

The Afteraction of Poultry Litter and Organo-Mineral Medium Based on it on the Field Crops Yield

В условиях полевого стационарного опыта на дерново-подзолистой среднесуглинистой почве изучено последействие куриного помёта и субстрата на его основе, с включением отхода тепличного производства, на урожайность и качественные показатели урожая яровой пшеницы и ярового рапса при отвальной и поверхностной системах основной обработки почвы. В опыте использован высушенный обеззараженный куриный помёт с содержанием питательных веществ: N – 2%; P2О5– 1,2%; К2О – 0,9% при влажности помёта 26,3% и отработанные вегетационные маты (минеральная вата IZOVOL AGRO UNIVERSAL). Результаты исследований показали, что внесённые в год закладки опыта куриный помёт и субстрат на его основе оказали положительное влияние на урожайность полевых культур в последующие два года, при этом степень влияния определялась и системой основной обработки почвы. В сумме за 2 года последействие куриного помёта и органо-минерального субстрата при отвальной обработке почвы близко по величине к действию минеральных удобрений, дополнение куриного помёта отходом тепличного комплекса незначительно снижало урожайность по сравнению с внесением куриного помёта. Максимальный урожай получен при использовании минеральных удобрений на фоне последействия органо-минерального субстрата – 60,87 ц/га к. ед., прибавка относительно варианта без применения удобрений составила 33,90 ц/га к. ед. (126%). При поверхностной обработке почвы продуктивность культур в сумме за два года ниже в сравнении с отвальной, прибавка получена только по фону последействия органо-минерального субстрата, причём также максимальная урожайность отмечалась при применении минеральных удобрений (13,63 ц/га к. ед. (43,6%)). Как ранее внесённый куриный помёт и органо-минеральный субстрат, так и минеральные удобрения способствовали увеличению выноса азота, фосфора, калия урожаем и накоплению сырого протеина в урожае зелёной массы ярового рапса на 3-й год после внесения. In the conditions of field stationary test on soddy podzolic middle loamy soils the afteraction of poultry litter and medium based on it was studied, with the inclusion of greenhouse production waste, on the yield and quality indicators of spring wheat and spring rape yields with moldboard and surface systems of primary tillage. The test used dried decontaminated poultry litter with nutrient content: N – 2%; P2О5 – 1.2%; К2О – 0.9% at litter humidity 26.3% and spent vegetation mats (mineral wool IZOVOL AGRO UNIVERSAL). The results of the researches showed that the poultry litter and medium introduced in the year of trial establishment had a positive effect on the yield of field crops in the next two years, while the degree of influence was also determined by the system of primary tillage. In total, for 2 years, the afteraction of poultry litter and organo-mineral medium in moldboard tillage is close in magnitude to the effect of mineral fertilizers, the addition of poultry litter by the waste of the greenhouse complex slightly reduced the yield compared to the introduction of poultry litter. The maximum yield was obtained using mineral fertilizers against the background of the afteraction of the organo-mineral medium – 60.87 c/ha f.u., the increase relative to the variant without using fertilizers was 33.90 c/ha f.u. (126%). With surface tillage the productivity of crops in the total for two years is lower compared to moldboard one, the increase was obtained only from the background of the afteraction of the organic-mineral medium, and the maximum yield was also noted when using mineral fertilizers (13.63 c/ha f.u. (43.6%)). Both the previously applied poultry litter and the organo-mineral medium and mineral fertilizers contributed to an increase in the yield of nitrogen, phosphorus, potassium by the crop and the accumulation of crude protein in the harvest of green mass of spring rape for the 3rd year after applying.

Cutinases obtained from filamentous fungi: comparison of screening methods

Cutinases are secreted by filamentous fungi that and hydrolyze polymers. However, few selection methods for cutinases are available. Here, we studied three screening methods using 33 strains of filamentous fungi isolated from banana rachis with high potential to produce cutinases. In the first method, strains were grown in Czapec-Dox mineral medium containing flaxseed oil. We note that six strains of the genera Fusarium, Penicillium, and Mucor had cutinase activity. The second method evaluated strains with triacetin in rhodamine B, which indicated what strains had esterase property. Finally, strains were subjected to fermentation with flaxseed oil; lipolytic and cutinolytic activity were determined. The species identified as the best producers of cutinases were Fusarium fujikuroi and Penicillium chrysogenum, and we obtained two extracellular cutinases with activities of 33.5 U/mL and 39.4 U/mL respectively. Cutinase was confirmed via degradation of tomato cutin through FTIR.

THE STRAIN GORDONIA SP. 135 — PROMISING DIBENZOTHIOPHENE DEGRADER

The genes supposedly involved in dibenzothiophene (DBT) degradation were identified in the genome of Gordonia sp. 135. The efficiency of DBT degradation was evaluated by high-performance liquid chromatography after strain cultivation in mineral medium (without sulfur) with glucose (hexadecane) as a carbon source at 28°C.