Significance of the presence of antibiotics on the microbial consortium in wastewater - The case of nitrofurantoin and furazolidone.

Antibiotics in wastewater leads to migration of pollutants and disrupts natural processes of mineralization of organic matter. In order to understand the mechanism of this, research was undertaken on the influence of nitrofurantoin (NFT) and furazolidone (FZD), on the behaviour of a consortium of microorganisms present in a model wastewater in a bioreactor. Our study confirmed biodegradation of the antibiotics by the microbial consortium, with the degradation efficiency within 10 days of 65% for FZD, but only 20% for NFT. The kinetic study proved that the presence of analysed antibiotics had no adverse effect on the microbes, but the consortium behaviour differ significantly with the NFT reducing the consumption of organic carbon in wastewater and increasing the production of extracellular biopolymeric and volatile organic compounds, and the FZD reducing assimilation of other carbon sources to a less extent, at the expense of cellular focus on biodegradation of this antibiotic

A novel approach in crude enzyme laccase production and application in emerging contaminant bioremediation

Laccase enzyme from white-rot fungi is a potential biocatalyst for the oxidation of emerging contaminants (ECs), such as pesticides, pharmaceuticals and steroid hormones. This study aims to develop a three-step platform to treat ECs: (i) enzyme production, (ii) enzyme concentration and (iii) enzyme application. In the first step, solid culture and liquid culture were compared. The solid culture produced significantly more laccase than the liquid culture (447 vs. 74 μM/min after eight days), demonstrating that white rot fungi thrived on a solid medium. In the second step, the enzyme was concentrated 6.6 times using an ultrafiltration (UF) process, resulting in laccase activity of 2980 μM/min. No enzymatic loss due to filtration and membrane adsorption was observed, suggesting the feasibility of the UF membrane for enzyme concentration. In the third step, concentrated crude enzyme was applied in an enzymatic membrane reactor (EMR) to remove a diverse set of ECs (31 compounds in six groups). The EMR effectively removed of steroid hormones, phytoestrogen, ultraviolet (UV) filters and industrial chemical (above 90%). However, it had low removal of pesticides and pharmaceuticals

Purification and immobilization of engineered glucose dehydrogenase: A new approach to producing gluconic acid from breadwaste

Background Platform chemicals are essential to industrial processes. Used as starting materials for the manufacture of diverse products, their cheap availability and efficient sourcing are an industrial requirement. Increasing concerns about the depletion of natural resources and growing environmental consciousness have led to a focus on the economics and ecological viability of bio-based platform chemical production. Contemporary approaches include the use of immobilized enzymes that can be harnessed to produce high-value chemicals from waste. Results In this study, an engineered glucose dehydrogenase (GDH) was optimized for gluconic acid (GA) production. Sulfolobus solfataricus GDH was expressed in Escherichia coli. The Km and Vmax values for recombinant GDH were calculated as 0.87 mM and 5.91 U/mg, respectively. Recombinant GDH was immobilized on a hierarchically porous silica support (MM-SBA-15) and its activity was compared with GDH immobilized on three commercially available supports. MM-SBA-15 showed significantly higher immobilization efficiency (> 98%) than the commercial supports. After 5 cycles, GDH activity was at least 14% greater than the remaining activity on commercial supports. Glucose in bread waste hydrolysate was converted to GA by free-state and immobilized GDH. After the 10th reuse cycle on MM-SBA-15, a 22% conversion yield was observed, generating 25 gGA/gGDH. The highest GA production efficiency was 47 gGA/gGDH using free-state GDH. Conclusions This study demonstrates the feasibility of enzymatically converting BWH to GA: immobilizing GDH on MM-SBA-15 renders the enzyme more stable and permits its multiple reuse

Biodegradation of chlorotoluene isomers in presence of natural surface active agents

Chlorinated derivatives of aromatic compounds are widely used in many industrial branches. Their emission into the environment poses a serious threat to organisms living in it. One of the major methods of their removal from the soil and water are biological methods based on the biodegradation of pollutants by the microorganisms present in the environment. Biodegradation of hydrophobic contaminants may be aided by the use of surfactants. In order to determine the effect of natural surfactants, saponins and rhamnolipids, on chlorotoluene isomers degradation by the soil strain Pseudomonas fluorescens, the measurements of chloride ion concentration, the quantity of emitted carbon oxide (IV) and the oxygen consumption of permanganate in liquid culture medium containing the test surfactants at various concentrations were conducted. In the cultures with saponinins and o- or p-chlorotoluene was the significant decrease of respiratory activity of microorganisms. However, in the cultures with m-chlorotoluene the saponin addition caused a little increase of CO2 concentration in headspace of cultures (2.5% in comparison with 2.2% for the culture without any surfactant). The study of oxygen consumption in samples from 10-days cultures indicated positive effect of rhamnolipids addition on biodegradation processes of all chlorotoluene isomers.Chlorowe pochodne związków aromatycznych są szeroko stosowane w wielu gałęziach przemysłu. Ich emisja do środowiska naturalnego stanowi poważne zagrożenie dla żyjących w nim organizmów. Jedną z głównych metod ich usuwania z gleb i wód są metody biologiczne oparte na biodegradacji zanieczyszczeń przez obecne w środowisku mikroorganizmy. Biodegradacja hydrofobowych zanieczyszczeń może być wspomagana poprzez zastosowanie surfaktantów. Aby określić wpływ naturalnych surfaktantów, saponin i ramnolipidów, na degradację izomerów chlorotoluenu przez szczep glebowy Pseudomonas fluorescens wykonano pomiary stężenia jonów chlorkowych, ilości tlenku węgla (IV) w fazie nadpowierzchniowej oraz utlenialności nadmanganianowej hodowli płynnych zawierających testowane surfaktanty w różnych stężeniach. W hodowlach z saponinami oraz o- lub p-chlorotoluenem nastąpiło znaczne obniżenie aktywności oddechowej mikroorganizmów, podczas gdy w hodowlach z m-chlorotoleuenem dodatek saponin w ilości 0,15 g/dm3 spowodował niewielki wzrost stężenia CO2 w fazie nadpowierzchniowej hodowli (2,5% w porównaniu do 2,2% w hodowli bez surfaktantu). Badania utlenialności próbek z hodowli po 10 dniach prowadzenia biodegradacji pokazały pozytywny efekt dodatku ramnolipidów na proces biodegradacji wszystkich trzech izomerów chlorotoleuenu

Spektroskopia w podczerwieni w ocenie modyfikacji powierzchniowych mikroorganizmów

Modyfikacje powierzchniowe mikroorganizmów są zmianami zachodzącymi na powierzchni komórek indukowanymi przez czynniki środowiskowe. Dzięki nim możliwa jest adaptacja drobnoustrojów do warunków otoczenia, która zapewnia im przetrwanie i efektywne wykorzystanie substratów metabolicznych. W przeprowadzonych analizach jako czynniki modyfikujące wykorzystano naturalne środki powierzchniowo czynne – saponiny. Surfaktanty te występują powszechnie w ekstraktach z różnych części roślin wyższych. W przedstawionych badaniach podjęto próbę oceny efektywności wykorzystania spektroskopii w podczerwieni w analizie modyfikacji właściwości powierzchniowych komórek mikroorganizmów zachodzących w wyniku dostępności określonych substratów w hodowli. Uzyskane wyniki potwierdzają, że spektroskopia FTIR może być stosowana jako metoda szybkiej i efektywnej identyfikacji zmian właściwości powierzchniowych bakterii

Hydroxyapatite as a support in protease immobilization process

Hydroxyapatite is used as a matrix for immobilization of protease from Aspergillus oryzae by a process of adsorption. The matrix obtained has the surface area of 26 m2/g and particles in the shape of flakes of diameters no greater than 650 nm. The efficiency of the proposed method was confirmed by the Fourier transform infrared spectroscopy, elemental analysis and by analysis of parameters of the pore structure of matrix and products after immobilization. On the basis of the Bradford method it was found that the greatest amount of enzyme (132 mg/g) was immobilized from a solution of initial enzyme concentration of 7 mg/cm3 after 24 h of the process

Electrospun biosystems made of nylon 6 and laccase and its application in dyes removal

Electrospun materials, due to the possibility of design of their properties, are suitable as supports for enzyme immobilization. Produced biocatalytic systems might be then apply in various biocatalytic reactions, including conversion of pollutants. In our study, electrospun fibers made from nylon 6 was produced, modified and applied as a support for laccase immobilization by adsorption and covalent binding. The systems with immobilized laccase were used in decolorization process of selected dyes, azo dye Reactive Black 5 and the anthraquinone dye Reactive Blue 4. It was found that at from dye solution at concentration 1 mg/L at pH 5, temperature 25 °C, after 24 h of process the efficiency of decolorization of Reactive Blue 4 and Reactive Black 5 reached 77% and 63%, respectively. The storage stability studies showed that after 30 days of storage, the relative activities were 60% and 95% for adsorbed and covalently bonded oxidoreductase respectively. Moreover, after 10 consecutive catalytic cycles adsorbed and covalently bonded laccase retained over 60% and 70% respectively, indicating the possibility of application of the obtained systems on a larger scale for removal of phenolic pollutants from wastewaters