Kinetics and optimization of process for isolation of plant extracts with antibacterial activity

Cilj ove doktorske disertacije bio je ispitivanje kinetike izolacije ekstrakata sa jakim antibakterijskim delovanjem iz biljnog materijala primenom različitih postupaka ekstrakcije. Za izolaciju bioaktivnih supstanci korišćena je natkritična ekstrakcija sa ugljenik(IV)-oksidom, hidrodestilacija i ekstrakcija etanolom sa i bez primene ultrazvuka. Predmetom istraživanja ove doktorske disertacije obuhvaćena je analiza i optimizacija različitih procesa izolacije, kao i ispitivanje sadržaja aktivnih komponenti i/ili antibakterijskog dejstva dobijenih ekstrakta za primenu u farmaceutskoj i/ili prehrambenoj industriji. U eksperimentima je, kao sirovina, korišćeno odabrano začinsko i lekovito bilje (Rosmarinus officinalis, Salvia officinalis, Thymus vulgaris, Origanum vulgare, Eugenia caryophyllata, Laurus nobilis, Angelica archangelica, Echinacea angustifolia, Verbascum thapsus, Calendula officinalis i Aloe barbadensis Miller), lišaj Usnea barbata i odabrane mešavine biljnog materijala (karanfilić/origano i karanfilić/timijan). U disertaciji je posebno ispitana i analizirana kinetika procesa natkritične ekstrakcije. S tim u vezi, ispitivan je uticaj operativnih parametara (pritiska i temperature) i odgovarajućeg predtretmana biljnog materijala sa natkritičnim ugljenik(IV)-oksidom na kinetiku natkritične ekstrakcije, kao i uticaj prisustva pojedinih biljnih sirovina u smeši (njihovih glavnih komponenata) na povećanje moći rastvaranja natkritičnog ugljenik(IV)- oksida (kosolventski efekat), pa samim tim i na povećanje brzine ekstrakcije i smanjenje potrošnje natkritičnog fluida. U disertaciji su, takođe, prikazani rezultati ispitivanja kinetike ekstrakcije etanolom sa i bez primene ultrazvuka. Za simulaciju procesa natkritične ekstrakcije iz pojedinačnih biljnih sirovina i izabranih mešavina biljnog materijala korišćeni su postojeći matematički modeli zasnovani na diferencijalnom bilansu mase (Stamenic i sar., 2008; Zizovic i sar., 2005; Sovova i sar., 1994a) i na analogiji sa prenosom toplote (Bartle i sar., 1990; Hong i sar., 1990; Reverchon i sar., 1994 i 1993). Odgovarajući parametri dobijeni primenom navedenih matematičkih modela, zajedno sa podacima o hemijskom sastavu, korišćeni su za interpretaciju fenomena prenosa mase u čvrstoj fazi i u filmu natkritičnog ugljenik(IV)-oksida do kojih dolazi tokom procesa natkritične ekstrakcije iz pojedinih biljnih sirovina i izabranih mešavina biljnog materijala. Za modelovanje procesa ekstrakcija sa etanolom korišćeni su postojeći modeli izvedeni iz drugog Fikovog zakona u cilju određivanja koeficijenata difuzije ekstraktivnih materija u čvrstoj fazi (Crank, 1975; Treybal, 1968). Za rešavanje jednačina navedenih matematičkih modela korišćen je softverski paket Microsoft Fortran PowerStation 4.0. Za ispitivanje antibakterijskog delovanja biljnih ekstrakata i etarskih ulja korišćenа је modifikovanа mikrodiluciona ili makrodiluciona metoda u bujonu opisana i preporučena od strane CLSI (Clinical Laboratory Standards Institute, 2008, SAD), koja se u rutinskoj laboratorijskoj praksi koristi za ispitivanje antibakterijskog delovanja antibiotika, tj. za određivanje vrednosti MIC (minimalne inhibitorne koncentracije) antibiotika. Antibakterijsko delovanje biljnih ekstrakata ispitivano је na sojevima: Staphylococcus vrsta, uključujući sojeve Staphylococcus aureus koji su rezistentni na meticilin (MRSA), Enterococcus vrsta (uključujući vankomicin rezistentne enterokoke, VRE), Streptococcus, Bacillus i Geobacillus vrsta. Ispitan je uticaj pojedinih ekstrakta i na sojeve Gram-negativnih bakterija, Е.coli, Enterobacter cloacae i Sallmonela Enteritidis...This study was aimed to investigate kinetics of isolation of the extracts with strong antibacterial activity from plant material by using different extraction processes. The bioactive substances from plant matrial were isolated by supercritical carbon dioxide extraction, hydrodistillation and ethanol extraction with and without ultrasound. The scope of the present study was kinetic analysis and optimization of different extraction processes as well as content of active substance and/or antibacterial activity of isolated supercritical extracts for application in pharmaceutical and/or food industry. Selected herbs and spices (Rosmarinus officinalis, Salvia officinalis, Thymus vulgaris, Origanum vulgare, Eugenia caryophyllata, Laurus nobilis, Angelica archangelic), Echinacea angustifolia, Verbascum thapsu, Calendula officinalis, Aloe barbadensis Miller), lichen Usnea barbata and selected mixtures of plant materials (clove/oregano and clove/thymus) were used as raw material for experiments. In this study, supercritical carbon dioxide extraction kinetics was particularly analyzed. Therewith, influence of operating parameters (pressure and temperature) and pretreatment of the plant material with supercritical carbon dioxide on the supercritical extraction kinetics, influence of presence of particular plant material in the mixtures of plants (their main components) on the solubility power of supercritical carbon dioxide (co-solvent effect) and subsquently on increase of extraction rate and reduction of supercritical fluid consumption was investigated in this work as well. The results of investigation of the kinetics of ethanol extractions are also presented here. Mathematical models based on differential mass balance (Stamenic et al., 2008; Zizovic et al., 2005; Sovova et al., 1994a,b) and heat transfer analogy (Bartle et al., 1990; Hong et al., 1990; Reverchon et al., 1994, 1993) were used for simulation of process of supercritical carbon dioxide extraction from pure plants and chosen mixture of plants for evaluation of parameters that can be used for interpretation of the mass transfer phenomena in the solid and supercritical carbon dioxide phase. Mathematical models based on the Second Fick’s Law were used for simulation of ethanol extractions in order to evaluate coefficients of diffusion of extractible substances in solid phase (Crank, 1975; Treybal, 1968). Solution of the equations of above metioned mathematical models were solved using Microsoft Fortran PowerStation 4.0. For antibacterial susceptibility testing, modified broth microdilution оr macrodilution method was applied in accordance with the prescription of CLSI (Clinical Laboratory Standards Institute, 2008, USA and corresponding MIC (minimal inhibitory concentration) values were determined. Antibacterial effect of plant extracts on Staphylococcus species including meticillin-resistant Staphylococcus aureus (MRSA) bacterial strains as well as Enterococcus (including vancomycin resistant strains–VRE), Streptococcus, Bacillus and Geobacillus species was investigated. Antibacterial activity of extracts on the Gram-negative bacteria such as Е.coli, Enterobacter cloacae and Sallmonela Enteritidis was investigated as well..

Restoration and conversion to re-use of historic buildings incorporating increased energy efficiency A Case Study - the Haybarn Complex, Hilandar Monastery, Mount Athos

A proper approach to restoration of historic buildings is crucial for monumental heritage protection. The objective of the paper is to define a methodology for historic buildings restoration in order to increase energy efficiency and re-usability in accordance with modern standards. The main method used in the paper is the observation of historic buildings during their restoration and exploitation, analysis and evaluation of achieved results regarding energy efficiency and energy saving, through the examples of the buildings belonging to Hilandar Monastery, Mount Athos, in Greece. Mount Athos was inscribed on the UNESCO World Heritage List for its cultural and natural values. This case study discusses the abandoned and dilapidated historic buildings of the Haybarn Complex (Stable, Mule keepers' House, and Haybarn), the achieved results regarding the restoration of these buildings, their energy efficiency and turning into the premises for occasional stays. The research results are recommendations for increasing energy efficiency while performing the restoration of historic buildings, so that these buildings could be re-used in a new way. The most significant contribution of the paper is the practical test of energy refurbishment of these historic buildings conducted using the principles and methods of energy efficiency, in compliance with conservation requirements and authenticity of historic buildings

Glass and Media Facades - Energy Refurbishment

Modern cities and their architectural structures undergo significant functional and physical changes. In recent years, the interventions on building envelopes have increased. Therefore, it is necessary to analyze potential remodeling of glass facades, along with applying the concept of smart technologies, in order to increase energy efficiency of the existing buildings. This paper analyzes the modernization process of devastated glass façade of the tall Slavija hotel, built in 1960s in Belgrade, Serbia, taking into consideration some positive examples of transformation and reskinning of buildings, where the aspect of medialization is an active part of urban renewal. The subject of this paper is the analysis of research findings about the improved thermal comfort of this building, after performing the replacement of its glass façade and converting the hotel building into a office building. Special attention was paid to the implementation of media facades technologies and final effects on energy balance of the newly designed facade. The proposed solution is supposed to evaluate the improved thermal comfort that was achieved by a radical renovation of the facade and by replacing the existing facade with a new single façade (double and triple glazed units), with media elements as well as without them. The research results are presented as proposals for improving EE public buildings by implementing the latest system of curtain walls in order to increase the value of the buildings. One of the most important criteria included in the process of energy refurbishment is technological improvement of the existing buildings, along with the presentation of media facades. The case study is based on Energy Plus simulations

Possibilities of energy efficient refurbishment of a family villa in Belgrade: a case study

A systematic approach to the restoration of an architectural structure is considered to be of crucial importance for its preservation. The objective of the research is to identify adequate methodologies for structural restoration in terms of energy efficiency, in accordance with modern requirements. The main method of this study is the observation of an architectural structure during its restoration and exploitation, and analysis and evaluation criteria for the findings regarding energy efficiency increase and energy saving. The subject of the research is a 1930s family villa in Belgrade, the analysis of the results achieved during the restoration of the villa in terms of energy efficiency and meeting modern living and comfort requirements. The study findings are recommendations for increasing energy efficiency during the restoration of a family villa in accordance with all modern living requirements. The key strategies to energy efficient refurbishment of the existing building are understanding and defining the already existing energy efficiency aspects of previous construction styles, in order to keep applying them efficiently, along with the latest construction methods. The study findings present the recommendations for increasing energy efficiency during restoration of the existing structures, while at the same time preserving the authenticity of those structures. The main contribution of the study is a practical evaluation of energy refurbishment of the restored structure, which is realized through various principles and measures of energy efficiency along with the use of renewable energy sources, in accordance with the conservation requirements and protection and preservance of authentic appearance of the building itself

Media architecture and sustainable environment

Being the integral part of a building, street or infrastructure, media contents shape the appearance of modern cities and affect the way their inhabitants act. The objective of this paper is to analyze the forms of communication that make the media contents useful. The communication between mediafacades and their environment is achieved by applying various sources of artificial light and mechanical systems. There are numerous advantages regarding media facades and their impact on certain buildings, city areas and regions. However, these façades are regarded to be the result of great technological achievements in the field of architecture and other spheres; therefore, certain problems are inevitably come across. This paper deals with the challenges in the media architecture and its interaction with cities and people as well as the users of media objects. Sustainability, visual and light comfort, visual and light pollution in cities, exaggerated importance ascribed to the perception of information technologies and architectural marketing focused on ’healthy life in cities’ are some of the topics included in this paper. One of the significant aspects that is to be considered carefully is appropriate ’positioning’ of media contents within a city, since there is a potential problem of excessive application of media contents in urban environment. This paper explores the ways in which everyday functioning in a city (noise, street lights, etc.) can affect the audio-visual qualities of media facades. Also, this work presents the methods of integrating the principles of sustainable architecture in the field of media architecture. Whenever it is possible, the principle of energy efficiency should be included in media-architecture design of new structures and remodeling of some old structures. Environmentally-aware development and reductions in energy consumption are the most important goals to be achieved in the field of media façade designs, regarding the phases of construction and media structures

Antibakterijsko delovanje mešavina ekstrakata usnee, timijana i anđelike dobijenih različitim tehnološkim procesima protiv nekih vrsta bakterija značajnih za veterinarsku medicinu

Antibacterial effects of plant extracts were examined using mixtures of extracts obtained using different technological processes: usnea extract was obtained using the process of supercritical extraction (NKE), angelica extract was obtained through supercritical extraction processes (NKE) and ultrasound extraction using ethanol (UZ), and thyme extract was obtained using the process of hydrodistillation (HD). Mixtures of the listed extracts were examined in various ratios: U (NKE) and T (HD) in a ratio of 1:1, U (NKE) and T (HD) in a ratio of 7:3, U (NKE), T (HD) and A (NKE) in a ratio of 2:2:1, and U (NKE), T (HD) and A (UZ) in a ratio of 2:2:1. The investigations covered 15 strains of bacteria of the genus Staphylococcus, Streptococcus and Enterococus, including the strains MRSA, VRE as well as reference strains of S. pyogenes ATCC 19615, S. agalactiae ATCC 27959 and S. aureus ATCC 11632. The antibacterial action of mixes of plant extracts was examined using the microdilution method in bouillon, and the examined mix concentrations were from 1.25 g/mL to 1280 g/mL. The strongest antibacterial effect was exhibited by mixes of usnea (NKE) and thyme (HD) in ratios of 1:1 and 7:3 with obtained MIC values from 5 g/mL to 160 g/mL, but the MIC value of the listed mixtures for the biggest number of strains amounted to 40 g/mL. A somewhat weaker effect was exhibited by the other examined extract mixtures with obtained MIC values of 10 g/mL to 320 g/mL. Based on the obtained MIC values and the results of previous investigations, it can be concluded that the examined mixtures of plant extracts exhibited a very strong antibacterial effect on the examined bacteria strains. .U ispitivanjima antibakterijskog delovanja biljnih ekstrakata korišćene su mešavine ekstrakata dobijenih primenom različitih tehnoloških procesa i to: ekstrakt usnee dobijen procesom natkritične ekstrakcije (NKE), ekstrakti anđelike dobijeni procesima natkritične ekstrakcije (NKE) i ultrazvučne ekstrakcije etanolom (UZ) i ekstrakt timijana dobijen procesom hidrodestilacije (HD). Ispitivane su mešavine navedenih ekstrakata u različitim odnosima: U(NKE) i T(HD) u odnosu 1:1, U(NKE) i T(HD) u odnosu 7:3, U(NKE), T(HD) i A(NKE) u odnosu 2:2:1 i U(NKE), T(HD) i A(UZ) u odnosu 2:2:1. Ispitivanjem je bilo obuhvaćeno 15 sojeva bakterija iz rodova Staphylococcus, Streptococcus i Enterococus, uključujući sojeve MRSA, sojeve VRE kao i referentne sojeve S. pyogenes ATCC 19615, S. agalactiae ATCC 27959 i S. aureus ATCC 11632. Antibakterijsko delovanje mešavina biljnih ekstrakata ispitivano je primenom mikrodilucione metode u bujonu, a ispitivane su koncentracije mešavina od 1,25 g/mL do 1280 g/mL. Najjače antibakterijsko delovanje pokazale su mešavine usnee (NKE) i timijana (HD) u odnosu 1:1 i 7:3 sa dobijenim vrednostima MIC od 5 g/mL do 160 g/mL, ali je vrednost MIC navedenih mešavina za najveći broj sojeva iznosila 40 g/mL. Nešto slabije delovanje pokazale su ostale ispitivane mešavine ekstrakata sa dobijenim vrednostima MIC od 10 g/mL do 320 g/mL. S obzirom na dobijene vrednosti MIC kao i na osnovu rezultata ranijih istraživanja, može se zaključiti da su sve ispitivane mešavine biljnih ekstrakata pokazale veoma jako antibakterijsko delovanje na ispitivane sojeve bakterija.

SUPERCRITICAL CO2 EXTRACTION OF OILS FROM RED GRAPE VARIETIES: YIELDS AND EXTRACTION PARAMETERS

In this work, the extraction by supercritical carbon (IV) oxide of grape seed oil from five red grape varieties were investigated. Apart from indigenous variety Prokupac, as a domestic, and Merlot and Cabernet Sauvignon, as  international grape varieties the most represented in Republic of Serbia, Pinot Noir and Gamay were studied as well. Extraction conditions were: temperature of 50 °C, 250 bar pressure and 0.3kg/h flow rate of CO2. It was shown that the extraction kinetics of international grape varieties, similar mutually differ significantly from domestic one. The obtained oil yields were in the range 8,3%w/w (Gamay) to 10,4%w/w (Pinot Noir) for international varieties and 4,96% w/w for domestic variety. Mathematical model “Sovova” was applied in order to define transport parameters regulating the oil mass transfer inside the seed particles and determine  agreement between experimental and model curves. The interpretation of results was done having in mind the differences of grade seed morphologies (outer surfaces and inner layers) which was investigated by SEM analysis

Impregnacija želatin-hitozan filmova etarskim uljem karanfilića pomoću natkritičnog co2 i njihova karakterizacija

Supercritical CO2 impregnation process was used for the first time to fabricate biodegradable gelatin-chitosan (G/Ch) films containing clove oil (CO) for potential use in active food packaging. All the impregnations were carried out at moderately low temperature (40 °C). Aiming to maximize CO loading in the films with acceptable morphological, structural and thermal properties, CO2 pressure, impregnation time and G:Ch mass ratio were varied. Gelatin fraction in the films of 25-50 wt.%, scCO2 pressures of 10-20 MPa and impregnation time of 2-6 h impregnation favoured the CO loading. Processing of the film with equal gelatin to chitosan mass ratio (G/Ch50:50) at 10 MPa for 2 h yielded sufficiently high loading (56 mg CO/gfilm) without an adverse effect on morphological properties. The G/Ch50:50 film was therefore chosen for structural and thermal analyses. ATR-FTIR analysis confirmed successful CO incorporation into the G/Ch50:50 and its interaction with the film. Plasticizing effect of scCO2 and CO on the film was evidenced by DSC. Incorporation of 56 mg CO/gfilm into the G/Ch50:50 didn't affect thermal stability of the film. Beside environmental benefits, supercritical impregnation process enables fast fabrication of G/Ch bio-composite films containing CO, thermally stable to 110 °C, which is suitable for most of food packaging applications. © 2019, CI and CEQ. All rights reserved

Reconstruction and revitalization of the complex Senara, within The Monastery Hilandar, in order to adapt to modern trends and social changes

The Holy Mount Athos is the cultural heritage of mankind. Until the mid-20th century the Holy Mount Athos had been visited only by rare pilgrims. Strict rules of monastic communities limited the number of potential followers. The monastery complex provided the accommodation for all visiting pilgrims. Modern life and significant social changes have increased the number of the people interested in visiting this monastic land. The endless flow of visitors and their frequent visits eventually began to disturb the lives of monks. That was one of the reasons that led to creating new accommodation capacities outside the monastery complex in order to provide the neccesary peace for the monks. The Monastery Hilandar, the fourth monastery in the hierarchy of the Holy Mount Athos monasteries and one of the most significant spiritual and cultural center of the Serbian people, was founded in 1198. In the immediate vicinity of the monastery of Hilandar walls there are abandoned and demolished facilities: stable, mulekeepers’ house and heybarn. These facilities were built in the beginning of the 19th century. Ten years ago, the reconstruction of the facilities started in order to restore the buildings and provide them with additional accommodation space for potential visitors. This paper presents the methods of reconstruction through a multidisciplinary approach based on architectural solutions and the aspects of comfort as well as the aspects of psychological and sociological mutual influence between two groups – the monks and the visitors. In this way, the carried out reconstruction revived the old facilities and gave them a new function that is adaptable to modern trends and social changes