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Pronalaženje i karakterizacija soja Bacillus sp. sa simultanom produkcijom α-amilaza i proteaza
No full textU ovom radu sproveden je pretraživanje i karakterizacija sojeva roda Bacillus sp. u cilju identifikacije mikroorganizma sposobnog za simultanu produkciju α-amilaze i proteaza. Od ukupno 64 testirane kolonije, odabrano je 15 sojeva sa uočenom hidrolitičkom aktivnošću, dok je soj označen kao Bacillus BB11 pokazao najvišu amilaznu aktivnost i odabran je za dalju analizu. Enzim je prečišćen jonoizmenjivačkom hromatografijom i okarakterisan metodama SDS-PAGE, zimograma i izoelektričnog fokusiranja. Određeni su temperaturni optimum (60 °C) i pH optimum (5,5), što ukazuje na stabilnost enzima u umerenim uslovima. Analiza proizvoda hidrolize skroba metodom TLC potvrdila je endo-mehanizam delovanja α-amilaze sa dominantnim formiranjem maltoze i maltotrioze. Paralelno je ispitana proteazna aktivnost soja BB11, koja pokazuje najveću aktivnost u baznom opsegu pH (oko 9,0), što ukazuje na prisustvo alkalne serinske proteaze. Dobijeni rezultati potvrđuju da soj Bacillus BB11 poseduje potencijal za primenu u biotehnološkim procesima fermentacije i valorizacije sirovina bogatih skrobom i proteinima
Reduction of Perfluoroalkyl Acids in Leachate from Industrial Waste Disposal Sites by Bacteria Isolated from Contaminated River Sediments
No full textSpecific chromogenic assay for detection of hippuricase-positive bacteria and its validation in raw chicken meat samples
No full textCampylobacter infections are behind most pathogenic food contamination cases in humans. Campylobacter jejuni is a pathogen commonly found in the food chain and especially in meat products. Contamination takes place already during the slaughtering process and affects the whole supply chain until the consumer. Campylobacter contamination is still hard to prevent, and this work reports a specific easy-to-read biochemical assay for live Campylobacter with a rapid visual detection from a small bacterial sample. Current PCR- and ninhydrin-based detection assay both present significant limitations in sustainability, applicability, and reliability. This work presents a biochemical easy-to-read assay for live Campylobacter proceeding in two steps and requiring water-based solutions for an improved safety and sustainability; moreover, it has been validated with chicken meat samples using mass-spectrometry techniques. The assay efficiently allows the discrimination of a microorganism having hippuricase activity, e.g. C. jejuni, from microorganisms without hippuricase activity as it delivers a bright pink color in positive samples
Application of VHH-Immobilized Cryogel-Based Immunoaffinity Chromatography for Isolation of Extracellular Vesicles
No full textExtracellular vesicles (EVs) are nanosized structures involved in intercellular communication that have high potential as disease biomarkers and for the delivery of therapeutic cargos. However, translation to the clinic is hampered by time-consuming, low-yield, and poorly reproducible EV isolation methods. We describe a cryogel-based immunoaffinity chromatography system that exploits single-domain VHH antibodies as capture elements for the selective isolation of EVs from human plasma. Supermacroporous cryogels functionalized with five unique anti-EV VHHs (total immobilization capacity ~500 μg/g) were prepared, yielding a highly permeable and hydrophilic support. They were captured and eluted under mild conditions, and their morphology and identity were confirmed by SEM, AFM, NTA, and flow cytometry. Proteomic profiling of the isolated samples identified 234 proteins, of which 63% were ExoCarta-listed exosomal proteins; contaminants such as albumin and apolipoproteins were also identified. The purification method provided samples with ~2 × 109 EVs/mL, with EV median size of 135 nm and consistent protein-to-lipid ratio across three independent isolations (CV < 10%). This study demonstrates that VHHfunctionalized cryogels (VHH-SMC) are a rapid and reproducible EV purification method that represents a promising alternative to conventional ultracentrifugation- or precipitationbased protocols. While optimization of nanobody density and reduction in plasma protein carryover are still necessary, the platform holds potential for scalable EV enrichment, a condition that can significantly speed up biomarker research and clinical diagnostics
Sustainable Integrated Approach to Waste Treatment in Automotive Industry: Solidification/Stabilization, Valorization, and Techno-Economic Assessment
No full textAn integrated approach to waste management is based on efficient and safe methods for
waste prevention, recycling, and safe waste treatment. In accordance with these principles,
in this study, non-hazardous aluminosilicate waste (dust and sand) was used in the solidification/
stabilization (S/S) treatment of hazardous waste (coating, emulsion, and sludge)
from the automotive industry. Also, the oily component of the waste was valorized and
investigated for energy recovery through co-incineration. The two S/S processes were proposed
and their sustainability was assessed by utilizing all types of waste generated in the
same plant, obtaining stabilized material suitable for safe disposal and oil phases for further
valorization, and by techno-economic analysis. The efficiency of the S/S processes was
evaluated by measuring unconfined compressive strength, hydraulic conductivity, density,
and the EN 12457-4 standard leaching test of S/S products, along with XRD, SEM-EDS, and
TG-DTG analyses. The possibility of using the oil phase was assessed based on its calorific
value. The techno-economic assessment compared the investments, operating costs, and
potential savings of both treatment scenarios. The results show that an integrated approach
enables safe waste immobilization and resource recovery, contributing to environmental
protection and economic benefits
Дигитализација наслеђа – фокусирање на личност из историје хемије
No full textПројекат „Дигитализација предмета из заоставштине Симе Лозанића“, акроним DELL, први овакав пројекат на Универзитету у Београду – Хемијском факултету. Неки од 260 предмета обухваћених овим пројектом су хемијске апаратуре, керамичко и стаклено посуђе, као и бочице са хемикалијама, повезани са овом важном личношћу. Сима Лозанић (1847-1935) је други школовани хемичар у Србији, академик, министар, државни испитивач руда и лажног новца, аутор многих уџбеника и чланака, али и реформатор образовања и пољопривреде у Србији. Лозанићева заоставштина се баштини у Збирци великана српске хемије, а повод за дигитализацију била је Година Симе Лозанића коју је прогласила Српска академија наука и уметности (САНУ).
Како би се јавности приближили величина и доприноси Лозанића, приређени су научни скуп у Свечаној сали САНУ, изложба „Сима Лозанић: витез српске науке“ ауторке Снежане Бојовић, изложба „Кабинет Симе Лозанића“ ауторки Јоване Тодоровић и Слађане Савић, као и филм „Сима Лозанић: без умора и одмора“ аутора Јоване Миловановић и Душана Цветића.
Надовезујући се на глобални императив и са циљем да се српско научно и техничко наслеђе учини доступнијим, у овом чланку се преносе искуства и смернице из пројекта DELL. Надамо се да ће стечени увиди бити корисни и другим музејима науке и технике у успешној реализацији сопствених пројеката дигитализацијеИнформације о пројекту: https://helix.chem.bg.ac.rs/projekti/233/index.htm
Application of spherical coordinates for coding ternary solvent mixture in the optimisation of Ganoderma resinaceum extraction
No full textMushrooms from the genus Ganoderma represent one of the most popular materials for
studying the medicinal properties of fungi. Species G. resinaceum, while less popular
than sister species G.lucidum, is still a goldmine of novel and potentially useful
metabolites. Due to the complex array of compound classes in such material, complex
solvent mixtures are needed to achieve the desired extract profile. A major obstacle in
choosing a suitable solvent mixture is the optimisation of component ratios. Response
surface methods, such as the Box-Behnken design (BBD), are widely employed to
identify the optimal conditions for a desired outcome systematically [1]. Another
important application involves determining the importance of each factor. Although
specialised mixture-type designs may be employed, these designs preclude the
incorporation of process parameters such as temperature, duration, and equipment
power. Another problem is the exponential growth of experimental runs needed when
adding more variables. In this work, the use of spherical coordinates [2] to code a ternary
solvent mixture using two variables was described. This greatly reduced the number of
experiments needed (about 35% less), saving time and resources. Within the framework
of the BBD, process parameters such as extraction time and power were optimised in
ultrasound-assisted extraction to identify the parameter combinations that maximise
yield. The relative importance of each solvent in the mixture was also elucidated. To the
best of our knowledge, this represents the first application of this methodology within
the context of natural product chemistry involving medicinal mushrooms
New Ru-arene complexes with 1,2,4-triazole Schiff base: synthesis, characterization, and cytotoxic evaluation
No full textZelena metodologija za ekstrakciju bakterijskih prirodnih proizvoda
No full textU ovom radu ispitana je primena zelenih rastvarača, posebno prirodnih eutektičkih smeša (NADES), za ekstrakciju bakterijskih biopigmenata prodigiozina i streptorubina. Posebna pažnja je posvećena optimizaciji ekstrakcionog sredstva, korišćenjem različitih kombinacija HBD i HBA komponenti NADES-a, u cilju zamene konvencionalnih organskih rastvarača ekološki prihvatljivijim alternativama. NADES rastvarači izabrani su zbog njihove niske toksičnosti, biorazgradivosti i sposobnosti rastvaranja biološki aktivnih jedinjenja. Ekstrakcija je izvedena iz biomase bakterija Serratia marcescens ATCC 27117 i Streptomyces sp. BPS43, nakon čega je sprovedeno prečišćavanje SPE metodom i praćenje sadržaja izolovanog pigmenta UV/VIS sprektrofotometrijom. Dobijeni rezultati pokazuju da ispitivane NADES smeše imaju značajno nižu efikasnost u odnosu na konvencionalne rastvarače, pri čemu su vrednosti koncentracija često bile ispod definisane optimalne granice. Najefikasnija NADES smeša za ekstrakciju prodigiozina bila je smeša glicerol : askorbinska kiselina = 5 : 1, dok je za streptorubin B najviši prinos dala smeša betain : mlečna kiselina = 1 : 1. Ipak, i ove smeše su bile znatno manje efikasne od konvencionalnih rastvarača, što se može pripisati strukturnoj otpornosti bakterijskog ćelijskog zida i ograničenoj sposobnosti NADES-a da prodru u ćeliju. Rezultati ukazuju da bi buduća poboljšanja mogla uključiti kombinovanje NADES rastvarača sa mehaničkim ili enzimskim tehnikama obrade. Sveukupno, rad potvrđuje vrednost NADES rastvarača kao održive alternative, ali i naglašava potrebu njihove dodatne optimizacije za primenu u ekstrakciji bakterijskih prirodnih proizvoda
Imipramine solubility-pH profiles: self-aggregation vs. common-ion effect
No full textBackground and purpose: The pH-dependent solubility of imipramine, a tricyclic antidepressant, and its hydrochloride salt was investigated in phosphate buffers and chloride-containing aqueous media using the pH-ramp shake-flask method. It was reported that aggregation of imipramine in acidic media and its partial degradation in alkaline media complicate the determination of its solubility. This was further investigated with modified methods. Experimental approach: For imipramine solubility studies, the computer program pDISOL-X was used to design experiments, process data, and refine the equilibrium constants. Isolated solid precipitates under various conditions were characterized using thermogravimetric analysis, differential scanning calorimetry, powder X-ray diffraction, and elemental analysis. The critical micelle concentration of imipramine hydrochloride was determined in 0.10 mol L-1 NaH2PO4 and in 0.15 mol L-1 NaCl by conducto-metric titrations. Key results: A detailed analysis of imipramine pH-solubility profiles reveals complex equilibria in the aqueous phase, as well as various solid-phase transformations. Intrinsic solubility of imipramine, solubility products of imipramine hydrochloride and imipramine phosphate salts, and aggre-gation constants (trimer, heptamer, and cationic complex with phosphate ions) were determined. Solid state characterization results are in accordance with pDISOL-X analysis. Conclusion: These findings, along with our previous solubility studies of desipramine and nortriptyline, suggest that even subtle structural variations can lead to significant differences in the aqueous media behaviour of tricyclic antidepressants. This type of information can be valuable in the early stages of drug discovery, in formulation optimization experiments, as well as in in vitro and in vivo studies