<p>Proizvodnja bioetanola iz među- i nusproizvoda procesa<br />prerade &scaron;ećerne repe, može imati pozitivan uticaj na<br />regionalnu ekomomiju i socio-ekonomski razvoj u zemljama<br />sa razvijenom industrijom konzumnog &scaron;ećera, kao &scaron;to je<br />Srbija. Kao proizvodni mikroorganizam u proizvodnji<br />etanola u najvećoj meri se koristi kvasac Saccharomyces<br />cerevisiae. Primena imobilisanih ćelija kvasca u fermentaciji<br />podloga sa visokom sadržajem &scaron;ećera (iznad 250 g/l), tzv.<br />VHG fermentacija, je često izučavana sa ciljem povećanja<br />efikasnosti proizvodnje etanola. U ovom radu su ćelije S.<br />cerevisiae imobilisane na različitim novim nosačima:<br />presovanim rezancima &scaron;ećerne repe (PR&Scaron;R), suvim<br />rezancima &scaron;ećerne repe (SR&Scaron;R), parenhimskom tkivu stabla<br />kukuruza (PTSK) u obliku diska, na kombinovanim<br />nosačima od PTSK u obliku diska obloženog Ca-alginatom(K1) i ispunjenog Ca-aglinatom (K2), na kuglicama Caalginata(AB) kao i na kombinovanim kuglicama od Caalginata i mliva PTSK (ABC). Imobilisane ćelije kvasca su primenjene za fermentaciju melase i gustog soka &scaron;ećerne repe sa krajnjim ciljem da se racionalnim kori&scaron;ćenjem</p><p>među- i nusproizoda procesa prerade &scaron;ećerne repe postigne<br />efikasna proizvodnja etanola uz smanjene tro&scaron;kove<br />proizvodnje kao, i uz smanjenje emisije otpadnih tokova.<br />U radu je ustanovljeno da su PR&Scaron;R, SR&Scaron;R i PTSK efikasni<br />nosači za imobilizaciju ćelija kvasca zahvaljujući prisustvu<br />pozitivno naelektrisanih funkcionalnih grupa, visokoj<br />poroznosti, hidrofilnosti, mehaničkoj čvrstini i stabilnosti.<br />Takođe ovi nosači &scaron;tite kvasac od osmotskog stresa,<br />toksičnog dejstva etanola i inhibitora. Zahvaljujući<br />heterogenoj strukturi PR&Scaron;R, SR&Scaron;R i PTSK se mogu koristiti<br />kao efikasni adsorbenti za ćelije kvasca, kao i za uklanjanje<br />katjonskih i anjonskih komponenata u postupku prerade<br />otpadnih voda. Pored toga, utvđeno je da PTSK predstavlja<br />alternativni obnovljivi izvor hranljivih materija neophodnih<br />kvascu tokom fermentacije melase i gustog soka, a takođe<br />deluje i kao antipenu&scaron;avac. Primenom ćelija kvasca<br />imobilisanih na SR&Scaron;R ostvarena je maksimalna<br />produktivnost etanola od 1,48 g/lh za melasu i 1,57 g/lh za<br />gusti sok, pri početnoj koncentraciji &scaron;ećera u podlozi 180 g/l.<br />Primenom ćelija kvasca imobilisanih na PTSK u obliku<br />diska (visine oko 5 mm i prečnika oko 20 mm) postignuta je<br />produktivnost etanola 1,26 g/lh za melasu 1,42 g/lh za gusti<br />sok, pri početnoj koncentraciji &scaron;ećera 150 g/l. Osnovni<br />nedostatak primene imobilisanih ćelija na SR&Scaron;R i PTSK u<br />alkoholnoj fermentaciji je lako ispiranje ćelija sa nosača.<br />Kombinovani nosači u obliku diska PTSK obloženog Ca alginatom<br />(K1) i ispunjenog Ca-aglinatom (K2) su<br />pripremljeni kako bi se sprečilo ispiranje ćelija kvasca.<br />Utvrđeno je da nosač K1 nije adekvatan za povećanje<br />efikasnosti imobilizacije. Imobilizacijom kvasca punjenjem<br />nosača K2 je povećana efikasnost imobilizacije ćelija kvasca<br />na PTSK, ali je usled velike zapremine i kompaktnosti<br />nosača K2 tokom fermentacije delimično otežan transport<br />supstrata i produkata kroz disk.<br />Melasa i gusti sok &scaron;ećerne repe su veoma dobre sirovine za<br />proizvodnju etanola, usled visokog sadržaja fermentabilnih<br />&scaron;ećera, koji slobodne i/ili imobiliane ćelije S. cerevisiae mogu<br />direktno koristiti za fermentaciju. Međutim, uzimajući u<br />obzir hemijski sastav ovih sirovina i ostvarene parametre</p><p>fermentacije, utvrđeno je da je gusti sok bolja sirovina za<br />proizvodnju etanola od melase, posebno u VHG uslovima.<br />Takođe je utvrđeno da se gusti sok može koristiti kao<br />sirovina za fermentaciju bez dodataka hranljivih materija.<br />Ustanovljeno je da su melase koje preostaju nakon osmotske<br />dehidratacije crvenog kupusa i mrkve veoma dobre sirovine<br />za proizvodnju etanola pri početnoj koncentraciji &scaron;ećera u<br />podlozi do 150 g/l, ali nisu pogodne sirovine za VHG<br />fermentaciju pomoću slobodnih i imobilisanih ćelija u AB<br />kuglicama. Fermentacijom melase nakon osmotske<br />dehidratacije kupusa i mrkve početne koncentracije &scaron;ećera<br />125 g/l, primenom ćelija kvasca imobilisanih u AB<br />kuglicama, ostvarena je najvi&scaron;a produktivnost etanola od<br />1,24 g/lh i 1,30 g/lh. Tokom fermentacije melase i gustog soka<br />primenom ćelija kvasca imobilisanih u AB kuglicama usled<br />izdvajanja CO2, dolazi do naru&scaron;avanja strukture kuglica<br />pojavom poprečne pukotine koja kuglicu polimera deli na<br />dva približno jednaka dela.<br />Kako bi se sprečila degradacija Ca-alginata tokom<br />fermentacije pripremljen je novi kombinovani nosač od Caalginata<br />i mliva PTSK (ABC). Dodatkom samlevenog PTSK<br />sa mikrostrukturom pčeljinjeg saća u Ca-alginat je povećana<br />poroznost kuglica čime je omogućen efikasniji prenos mase<br />supstrata i produkata, povećana je raspoloživa povr&scaron;ina za<br />adsorpciju i rast ćelija kvasca kao i čvrstina i stabilost<br />kuglica. Poređenjem parametara fermentacije, utvrđeno je<br />da su ćelije kvasca imobilisane na ABC kuglicama efikasniji<br />biokatalizator u poređenju sa slobodnim ćelijama kvasca,<br />kao i u poređenju sa ćelijama imobilisanim u AB kuglicama.<br />Dodatkom samlevenog PTSK u podlogu ili u Ca-alginat<br />povećava se sadržaj etanola i metanola, smanjuje se sadržaj<br />kiselina i acetaldehida u sirovom destilatu, dok se sadržaj<br />vi&scaron;ih alkohola, estara i furfurala ne menja značajno. Ćelije<br />kvasca imobilisane u kombinovanim ABC kuglicama se<br />mogu uspe&scaron;no primeniti za pet ponovljenih fermentacija<br />gustog soka pri standardnim (NG) i uslovima visoke<br />koncentracije &scaron;ećera (VHG) pri čemu se može postići<br />produktivnost etanola 1,92-2,30 g/lh. Primenom imobilisanih<br />ćelija kvasca u kombinovanim ABC kuglicama u<br />kontinualnoj VHG fermentaciji gustog soka, početne<br />koncentracije &scaron;ećera 300 g/l, ostvaren je stabilan<br />fermentacioni sistem tokom 15 dana, pri čemu je<br />produktivnost etanola iznosila 3,29 do 4,66 g/lh.</p> / <p>Bioethanol production from intermediate and byproducts<br />of sugar beet processing has a beneficial scope<br />in view of the socio-economic development and regional<br />economy in countries with developed sugar industry,<br />such as Serbia. Saccharomyces cerevisiae strain is the<br />most widely used ethanol producing microorganism. To<br />increase the efficiency of ethanol production, many<br />process improvements including immobilized cells<br />application and fermentation of very high gravity (VHG)<br />media with initial sugar over 250 g/l, have been studied.<br />In the present work yeast S. cerevisiae was immobilized<br />onto different new carriers: pressed sugar beet pulp<br />(PSBP), dried sugar beet pulp (DSBP), maize stem<br />ground tissue (MSGT) disks, MSGT discs coated with<br />Ca-alginate (K1) and MSGT discs filled with Ca-alginate<br />(K2), Ca-alginate beads (AB) and combined beads made</p><p>of Ca-alginate and maize stem ground tissue meal (ABC).<br />Immobilized yeast cells were used for ethanol<br />fermentation of molasses and thick juice with purposes to<br />obtain efficient ethanol production, to lower high<br />operating costs and to achieve the zero-waste goal<br />through a rational use of by-products of sugar beet<br />processing.<br />In the present work it was found that PSBP, DSBP and<br />MSGT are efficient carriers for yeast cell immobilization<br />due to the presence of positively charged binding sites,<br />high porosity and hidrophylicity, good mechanical<br />strength and stability, while functioned as a fortification<br />against osmotic stress, toxins and inhibitors. It was also<br />found that due to the heterogeneous structure the PSBP,<br />DSBP and MSGT are promising adsorbents for the<br />removal of cationic and anionic compounds from<br />aqueous solutions in the waste water treatment. Besides,<br />it is found that the MSGT can be used as an alternative<br />nutrient source for yeast cells and as an anti foaming<br />agent. A maximum ethanol productivity of 1.48 g/lh and<br />1.57 g/lh was achieved in the fermentation of molasses<br />and thick juice (initial sugar of 180 g/l) using yeast<br />immobilized on DSBP. The highest values of ethanol<br />productivity, obtained in the case of using yeast<br />immobilized on MSGT discs as biocatalyst, for molasses<br />and thick juice (initial sugar of 150 g/l) fermentation<br />were 1.26 g/lh and 1.42 g/lh. The main disadvantage of<br />using DSBP and MSGT supported biocatalyst is intensive<br />leakage of yeast cells during the fermentation. In order to<br />prevent yeast leakage combined carriers in the form of<br />MSGT discs coated with Ca-alginate (K1) and MSGT<br />discs filled with Ca-alginate (K2) were prepared. The K1<br />carrier was found to be unsuccessful for improving yeast<br />immobilization efficiency, while the application K2<br />carrier improved yeast immobilization efficiency during<br />the fermentation. However, due to the large volume and<br />compactness of the K2 carrier substrate and product<br />mass transfer limitation were observed during the<br />fermentation.<br />The sugar beet molasses and thick juice are very good<br />raw materials for ethanol production due to high content<br />of fermentable sugars, which can be directly used for<br />fermentation by free and/or immobilized S. cerevisiae<br />cells without any modification. However, taking into</p><p>consideration quality of these raw materials and obtained<br />fermentation parameters, sugar beet thick juice was<br />found to be more suitable raw material for ethanol<br />fermentation, compared to molasses, particularly in the<br />VHG fermentation process and can be used without any<br />nutrient supplementation. Similarly, it was found that<br />molasses left after the osmotic dehydratation of red<br />cabbage (M1) and carrots (M2) are excellent raw<br />materials for ethanol fermentation of media with initial<br />sugar concentration up to 150 g/l, while they are not<br />convenient for VHG fermentation by free or immobilized<br />yeast cells in AB carrier. Maximum ethanol productivity<br />obtained at the end of fermentation of molasses M1 and<br />M2 by immobilized yeast in AB carrier was 1.24 g/lh and<br />1.30 g/lh, respectively. The release of CO2 during the<br />fermentation of molasses and thick juice by yeast cells<br />immobilized in the AB, lead to breakage of polymer<br />beads on two halves.<br />In order to prevent AB disruption, a new combined yeast<br />carrier (ABC) was developed by the addition of MSGT<br />meal into the Ca-alginate. It was found that the addition<br />of MSGT meal, with honeycomb microstructure,<br />provided large surface area for yeast cell attachment and<br />biofilm growth, and also increased alginate matrix<br />porosity, enabling better mass transfer characteristic,<br />better physical strength and stability of beads. The<br />highest values of fermentation parameters were obtained<br />in the fermentation system with yeast immobilized on<br />ABC carrier in comparison with free yeast cells and yeast<br />immobilized on AB carrier. The Ca-alginate and medium<br />supplementation with MSGT meal significantly increased<br />ethanol and methanol content, decreased acetaldehyde<br />and acetic acid content of the distillate, but did not affect<br />fusel alcohol, ester and furfural content of the distillate.<br />Repeated batch normal gravity (NG) and very high<br />gravity (VHG) ethanol fermentation of thick juice by<br />yeast immobilized on ABC carrier was successfully<br />carried out for at least five successive cycles without any<br />significant decrease in ethanol productivity which was in<br />the range 1.92-2.30 g/lh. Continuous VHG ethanol<br />fermentation of thick juice (initial sugar of 300 g/l) using<br />yeast immobilized on ABC was stable for at least 15 days<br />while achieved ethanol productivity was 3.29-4.66 g/lh.</p>

<p>Uvod: Hepatička osteodistrofija je termin koji obuhvata metaboličke bolesti kosti udružene sa hroničnim bolestima jetre. U alkoholnoj cirozi (AC) jetre postoji visoka zastupljenost deficijencije vitamina D proporcionalna stepenu disfunkcije jetre, ali njena uloga u patogenezi hepatičke osteodistrofije nije dovoljno obja&scaron;njena. Nivo 25(OH)D odražava status vitamina D. Kod AC jetre izmenjena je metabolička aktivnost kosti i suprimirano je formiranje kosti &scaron;to dovodi do smanjenja ko&scaron;tane mase. U centru interesovanja je postizanje optimalnog statusa vitamina D. Stavovi o suplementaciji vitaminom D kod AC jetre nisu jasno definisani. Cilj rada: Utvrditi nivo vitamina D, ispitati metaboličku aktivnost kosti i mineralnu gustinu kosti kod bolesnika sa AC jetre. Utvrditi efekte suplementacije sa 1000 IU vitamina D3 na dan tokom godinu dana u odnosu na metaboličku aktivnost kosti i mineralnu gustinu kosti kod ispitivanih bolesnika. Bolesnici i metode: Istraživanje je sprovedeno na Klinici za gastroenterologiju i hepatologiju Kliničkog centra Vojvodine u Novom Sadu kao prospektivna intervencijska studija sa primenom suplementacije sa 1000 IU vitamina D3 na dan kod bolesnika sa AC jetre. Grupu bolesnika koja je uključena u istraživanje (1) činilo je 70 bolesnika mu&scaron;kog pola sa dijagnozom AC jetre. Bolesnici su imali četiri pregleda (P), odnosno tačke studije: P1-uključivanje bolesnika i započinjanje suplementacije vitaminom D; P2, P3 i P4 posle tri, &scaron;est i dvanaest meseci suplementacije vitaminom D, redom. Prilikom svakog pregleda rađene su analize funkcije jetre, metabolizma kosti i statusa vitamina D. Na početku (P1) i na kraju istraživanja (P4) vr&scaron;eno je merenje mineralne gustine kosti (BMD) DXA metodom. Gubitak bolesnika od P1 do P4 bio je dvadeset, na različitim tačkama studije. Prvi deo istraživanja odnosi se na Grupu bolesnika koja je uključena u istraživanje (1) i zavr&scaron;ila prvi pregled (P1). Pedeset bolesnika je zavr&scaron;ilo kompletno istraživanje po predviđenom protokolu i oni se zbog realizacije svih pregleda i ponovljenih merenja posmatraju kao: Grupa bolesnika koja je zavr&scaron;ila istraživanje (2). Rezultati: (1): Kod bolesnika sa AC jetre utvrđena je deficijencija vitamina D, snižen nivo osteokalcina, normalni nivoi CrossLapsa, PTH, ukupnog i jonizovanog kalcijuma, fosfora i magnezijuma. Osteopeniju je imalo 42,65% a osteoporozu 14,71% ispitanika. Kod svih ispitanika najniži BMD izmeren je na vratu femura. (2): Suplementacija vitaminom D dovela je do značajnog porasta 25(OH)D. U odnosu na osteokalcin konstatovana je pozitivna razlika vrednosti P1/P4, iako je nivo ostao ispod donje granice normale. Kod nivoa CrossLapsa i PTH razlika P1/P4 je negativna, ali su nivoi u sva četiri merenja u okviru referentnih vrednosti. Na lumbalnoj kičmi do&scaron;lo je do pobolj&scaron;anja BMD za 0.87%, a pogor&scaron;anja su na vratu femura -1.87 % i kuku -1.65%. Konstatovano je i pobolj&scaron;anje funkcije jetre. Zaključci: Kod bolesnika sa AC jetre pobolj&scaron;anje statusa vitamina D dovodi do povećanja formiranja kosti i pobolj&scaron;anja ko&scaron;tane mase na lumbalnoj kičmi. Neophodno je određivanje statusa vitamina D kod svih bolesnika sa AC jetre i uvođenje suplementacije vitaminom D kod bolesnika koji imaju nivo 25(OH)D &lt; 80 nmol/l, uz tromesečne kontrole efekta. Kod postavljanja dijagnoze AC jetre potrebno je inicijalno određivanje BMD. Kod suplementacije vitaminom D nakon inicijalnog DXA pregleda sledeći se preporučuje nakon jedne do dve godine.</p> / <p>Introduction: The term Hepatic osteodystrophy defines a group of metabolic bone diseases associated with underlying chronic liver disease. Alcoholic liver cirrhosis (ALC) is characterized by high incidence of vitamin D deficiency that is proportional to the level of liver failure; however, its role in the pathogenesis of hepatic osteodystrophy has not yet been fully elucidated. The level of 25(OH)D best reflects the vitamin D status. ALC is characterized by changed bone metabolic activity and suppressed bone formation, resulting in the decrease in bone mass. The key topic of interest is the achievement of optimal vitamin D status. The attitude of health professionals towards vitamin D supplementation in alcoholic liver cirrhosis has not yet been clearly defined. The aim of the research: Determining of vitamin D levels, investigating the metabolic activity of the bone and bone mass in patients with alcoholic liver cirrhosis (ALC); Determining the effects of vitamin D3 supplementation at the dose 1000 IU/day during a one-year period in relation to metabolic activity of the bone and bone mineral density (BMD) in the investigated patient population. Patients and methods: The research was conducted at the Clinic for Gastroenterology and Hepatology of the Clinical Centre of Vojvodina in Novi Sad. The research was designed as a prospective interventional study implicating vitamin D3 supplementation at the dose 1000 IU/day to patients with ALC. The investigated patient population (1) encompassed 70 male patients diagnosed with ALC. The patients underwent four examinations (P), that is, research phases: P1 &ndash; inclusion of the patient into the study and introduction of vitamin D supplementation; P2, P3 and P4 after 3, 6 and 12 months of vitamin D supplementation treatment, respectively. Each examination included the analysis of liver function, bone metabolism and vitamin D status. At the beginning (P1) and at the end (P4) of the investigation period, bone mineral density (BMD) was measured by means of dual-energy x-ray absorptiometry (DXA) method. Twenty patients dropped out from the research at different stages throughout the investigation period (P1 to P4). The first part of the investigation pertains to the Group of patients who were included into the study (1) and completed the first examination (P1). Fifty patients have completed the entire research according to the foreseen protocol encompassing all examinations and repeated measurements. These patients are considered a Group of patients who completed the research (2) Results: (1): In ALC patients, vitamin D deficiency and decreased osteocalcin levels were established, as well as normal levels of CrossLaps, PTH, total and ionized calcium, phosphorus and magnesium. Osteopenia and osteoporosis were established in 42.65% and 14.71% of patients, respectively. The lowest BMD was measured in the femoral neck in all patients. (2): Vitamin D supplementation resulted in significant increase in 25(OH)D. Analysis of osteocalcin level revealed positive P1/P4 difference, even though the level remained below the lower normal limit. The levels of CrossLaps and PTH revealed negative P1/P4 difference; however, the levels determined at all four measurements were within the reference values. An improvement of BMD for 0.87% was established in lumbar spine, whereas a decrease was noticed in femoral neck (1.87%) and hip (1.65%). Furthermore, an improvement of liver function was established. Conclusions: Improvement of vitamin D status in ALC patients results in an increase of bone formation and improvement of body mass in lumbar spine. Determining the vitamin D status in all patients with ALC is of outmost importance, as well as the vitamin D supplementation of patients with levels of 25(OH)D &lt; 80 nmol/l along with the monitoring of treatment outcome at three-month intervals. Establishment of the diagnosis of alcoholic liver cirrhosis should encompass initial measurement of BMD. In case of vitamin D supplementation treatment, the initial DXA examination should be repeated after the period of one to two years.</p>