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Maize (Zea mays L.) is one of the most important cereal crops, and as such, one of the most significant naturally renewable carbohydrate raw materials for the production of energy and multitude of different products. Many studies have shown that the kernel composition and starch structure of maize are highly influenced by genetic background of the maize. Maize grain consists of approximately 70% of starch, which makes it a very suitable feedstock for the bioethanol production. This study was conducted with aim to understand how different genetic background affects bioethanol yield and other fermentation properties of the selected maize genotypes in the process of maize grain-based bioethanol production. Twenty seven maize hybrids, including genotypes of standard chemical composition as well as specialty maize hybrids such as popping, waxy, white kernel and red kernel hybrids, developed at the Maize Research Institute, Zemun Polje, were investigated in this study. The lowest bioethanol yield of 7.25% w/w obtained for hybrid ZP 611k after 48 h of fermentation and the highest by genotype ZP 434 (8.96% w/w). A very significant positive correlation was determined between kernel starch content and the bioethanol yield after 48h of fermentation, as well as volumetric productivity (48h) (r=0.67). Between bioethanol yield after 48h of fermentation and soft endosperm content in kernel of the investigated ZP maize hybrids a very significant positive correlation was assessed (r=0.66). Higher overall bioethanol yields have been obtained from genotypes containing higher starch and lower protein and lipid contents.

Utilization of distillery stillage from bioethanol production for lactic acid and feed production was studied. The lactic acid fermentation of the stillage was performed by Lactobacillus rhamnosus ATCC 7469 and maximal lactic acid concentration of 50.18 g L-1, yield of 0.90 g g(-1), productivity of 1.48 g L-1 h(-1) and viable cell number of 5 x 10(9) CPU mL(-1) were achieved. Solid residues with biomass remains after lactic acid fermentation were assessed for animal consumption. The content of proteins and ash decreased in the residues after the fermentation, whilst the content of oil and nitrogen free extract was higher when compared to unfermented samples. The digestible (17480.64 kJ kg(-1)) and metabolisable (17389.08 kJ kg(-1)) energies as well as digestibility (966.95 g kg(-1)) of the fermentation residue were very high. The in vitro assessment of L. rhamnosus ATCC 7469 survival in simulated gastric conditions has shown high survival rate (87%). In addition, this bacterium has shown good antimicrobial activity against the most important pathogens and capability to produce exopolysaccharide on different sugars present in animal diet. After effective lactic acid fermentation, the residues could be recommended as a high quality feed for monogastric animals.

Maize (Zea mays L.) is one of the most important cereal crops. and one of the most significant renewable raw materials for the production of energy and many different products. Bioethanol is a biofuel that is mostly used as a replacement for fossil fuels worldwide. Major by­product that arises from the fermentation process of corn is dried distillers' grains (DDG). Due to its high feeding value it represents an excellent component for livestock feed mixtures. The main goal of this study was to determine the technological quality of maize grain and the influence of maize hybrid on bioethanol yield and quality of this process' by-product, dried distillers' grains. Five maize hybrids developed at the Maize Research Institute, Zemun Polje, were investigated in this study. The lowest concentration of bioethanol in the fermentation medium after 44h of alcoholic fermentation (8.64% w/w) was obtained by hybrid ZP 560, and the highest (9.10% w/w) by hybrid ZP 600, while compared to the maximum theoretical bioethanol yield, the highest scoring hybrid was ZP 606 (93.59%) and the lowest ZP 505 (87.33%). The highest in vitro dry matter digestibility of DDG was determined in a sample obtained from hybrid ZP 505 (82.41%) and the lowest (77.12%) in the DDG sample of ZP 606. The chemical composition and physical characteristics of the grain, as well as other parameters of the production process have influenced the overall bioethanol yield. Hybrids created in the Maize Research Institute represent unique starting material for research of the possibilities of bioethanol, starch, food and animal feed production., Kukuruz (Zea mays L.) je jedna od najznačajnijih ratarskih biljaka koja se svrstava u veoma važne obnovljive ugljenohidratne sirovone za proizvodnju energije i mnogobrojnih proizvoda različite namene. Bioetanol je biogorivo koje se najviše koristi kao zamena za fosilna goriva. Trend proizvodnje ovog goriva je rastući, a kukuruz zahvaljujući visokom sadržaju skroba u zrnu, predstavlja jednu od najboljih obnovljivih sirovina za njegovu proizvodnju. Suva kukuruzna džibra je najznačajniji sporedni proizvod dobijanja bioetanola iz kukuruza. Zahvaljujući visokoj hranljivoj vrednosti, sadržaju proteina i drugih hranljivih materija, predstavlja kvalitetno hranivo koje može naći primenu kao komponenta u smešama za ishranu životinja. U cilju ispitivanja uticaja hibrida kukuruza na kvalitet zrna, fermentaciona svojstva, prinos bioetanola i kvalitet suve kukuruzne džibre korišćeno je zrno pet hibrida kukuruza stvorenih u Institutu za kukuruz 'Zemun Polje'. Najnižu koncentraciju bioetanola u fermentacionom medijumu nakon 44h alkoholnog vrenja (8,64 % w/w) ostvario je hibrid ZP 560 a najvišu ZP 600 (9,10 % w/w). U odnosu na maksimalni teorijski prinos najviši je imao hibrid ZP 606 (93,59%), a najniži ZP 505 (87,33%). Najveća in vitro svarljivost suve materije kukuruzne džibre određena je u uzorku dobijenom od hibrida ZP 505 (82,41%), a najniža (77,12%) u uzorku džibre hibrida ZP 606. Hemijski sastav i fizičke karakteristike zrna, kao i drugi parametri procesa proizvodnje uticali su na prinos bioetanola.

Utilization of distillery stillage from bioethanol production for lactic acid and feed production was studied. The lactic acid fermentation of the stillage was performed by Lactobacillus rhamnosus ATCC 7469 and maximal lactic acid concentration of 50.18 g L-1, yield of 0.90 g g(-1), productivity of 1.48 g L-1 h(-1) and viable cell number of 5 x 10(9) CPU mL(-1) were achieved. Solid residues with biomass remains after lactic acid fermentation were assessed for animal consumption. The content of proteins and ash decreased in the residues after the fermentation, whilst the content of oil and nitrogen free extract was higher when compared to unfermented samples. The digestible (17480.64 kJ kg(-1)) and metabolisable (17389.08 kJ kg(-1)) energies as well as digestibility (966.95 g kg(-1)) of the fermentation residue were very high. The in vitro assessment of L. rhamnosus ATCC 7469 survival in simulated gastric conditions has shown high survival rate (87%). In addition, this bacterium has shown good antimicrobial activity against the most important pathogens and capability to produce exopolysaccharide on different sugars present in animal diet. After effective lactic acid fermentation, the residues could be recommended as a high quality feed for monogastric animals.

This paper presents results of studies on qualities of maize dried distillers' grains with solubles (DDGS), as animal feed, which is a by-product from the process of maize grain-based bioethanol production. Twenty maize hybrids, developed at the Maize Research Institute, Zemun Polje, were used in this study. The moisture content in all DDGS samples was below 13% - the maximum value according to the Serbian Regulation. Furthermore, obtained results show that all observed DDGS samples had a high content of protein (29.58 - 36.08%), i.e. three-fold higher than in the initial raw material - maize grain. The digestibility of dry matter in samples of DDGS ranged from 74.09 (ZP Rumenka) to 82.41% (ZP 505). Based on obtained results, samples of DDGS were of high quality and therefore can be used as feed for the preparation of complete and concentrated feed., Proizvodnjom bioetanola od zrna kukuruza dobija se sporedni proizvod poznat kao kukuruzna džibra. Na svaki litar bioetanola proizvedenog od zrna kukuruza nastaje oko 0,89 kg suve kukuruzne džibre. Ovaj sporedni proizvod industrije bioetanola predstavlja odličan izvor proteina i energije pa se zbog toga najčešće koristi kao komponenta smeša za ishranu domaćih životinja. Prihod od prodaje suve kukuruzne džibre mogao bi da ima pozitivan uticaj na ekonomsku isplativost proizvodnje bioetanola postupkom suvog mlevenja s obzirom da se ovim procesom jedna trećina kukuruznog zrna prevodi u suvu džibru. U ovom radu prikazani su rezultati ispitivanja kvaliteta suve kukuruzne džibre, kao hraniva za životinje. U istraživanju je korišćeno 20 hibrida kukuruza Instituta za kukuruz 'Zemun Polje '. Sadržaj suve materije kretao se od 90,47 (ZP Rumenka) do 91,87% (ZP 362), što ukazuje da je sadržaj vlage u svim uzorcima bio manji od 13%, maksimalne vrednosti prema Pravilniku o kvalitetu hrane za životinje. Rezultati su pokazali da su svi ispitani uzorci imali visok sadržaj proteina, između 29,58 (ZP 505) i 36,08% (ZP 611k). Pored toga uočeno je da je sadržaj proteina u suvoj džibri skoro utrostručen u odnosu na zrno kukuruza kao polaznu sirovinu. Svarljivost suve materije uzoraka suve kukuruzne džibre kretala se u rasponu od 74,09 (ZPRumenka) do 82,41% (ZP 505). Na osnovu dobijenih rezultata ustanovljeno je da su uzorci suve džibre svih ispitivanih hibrida dobrog kvaliteta i mogu se koristiti kao hranivo za pripremu potpunih i koncentrovanih smeša za ishranu životinja.

Bioetanol je biogorivo koje se širom sveta najviše koristi kao zamena za fosilna goriva. Trend proizvodnje ovog goriva je rastući, a kukuruz predstavlja jednu od najboljih obnovljivih sirovina za njegovu proizvodnju zahvaljujući visokom sadržaju skroba u zrnu. Suva džibra sa rastvorenim materijama (SDžSRM) je najznačajniji sporedni proizvod procesa proizvodnje bioetanola iz kukuruza. Zahvaljujući visokoj hranljivoj vrednosti, sadržaju proteina i drugih hranljivih materija, predstavlja kvalitetno hranivo koje može naći primenu kao komponenta u smešama koje se koriste za ishranu životinja. Procesom mokrog mlevenja zrna kukuruza se osim skroba, koji je osnovni proizvod od velikog značaja za prehrambenu i druge industrije, dobijaju vredni sporedni proizvodi koji takođe mogu naći primenu u ishrani ljudi i životinja. U teorijskom delu ove disertacije dat je sveobuhvatni prikaz svetskih trendova u proizvodnji bioetanola. Predstavljene su savremene tehnologije prerade kukuruza koje se koriste u proizvodnji ovog alternativnog goriva i skroba kao i inovacije koje se razvijaju u cilju poboljšanja efikasnosti i ekonomske isplativosti ovih postupaka. Hibridi kukuruza stvoreni u Institutu za kukuruz "Zemun Polje" predstavljaju jedinstven polazni materijal za istraživanja mogućnosti proizvodnje bioetanola, skroba i hrane za životinje. Cilj ovih istraživanja bio je da se polazeći od drugačijih fizičkih karakteristika i hemijskog sastava hibrida standardnog kvaliteta zrna i hibrida specifičnih svojstava različite genetičke osnove utvrdi na koji način i u kojoj meri ova svojstva zrna utiču na prinos i kvalitet finalnih proizvoda. Određena su fizička svojstva i hemijski sastav zrna ispitivanih hibrida kukuruza. Izvršena je optimizacija procesa enzimske hidrolize i alkoholne fermentacije brašna celog zrna odabranih hibrida kukuruza primenom enzima termostabilne α-amilaze Termamyl SC i glukoamilaze SAN Extra L, kao i proizvodnog mikroorganizma - kvasca Saccharomyces cerevisiae var. elli, Bioethanol is a biofuel that is mostly used as a replacement for fossil fuels worldwide. Trends of producing this alternative fuel are rising and maize is one of the best renewable raw materials for the production of fuel ethanol due to the high content of starch in the grain. Major by-product that arises from the fermentation process of corn is dried distillers’ grains with solubles (DDGS). Due to its high feeding value, high protein and other valuable nutrients it represents an excellent component for livestock feed mixtures. Corn grain wet milling process produces apart from corn starch, which is the main product of great importance to the food and other industries, valuable by-products, which may also find their applications in human and animal nutrition. In the theoretical part of this dissertation a comprehensive overview of global trends in the production of bioethanol was made. State of the art technologies of corn grain processing used in the production of this alternative fuel and starch, as well as innovations that are being developed in order to improve the efficiency and cost-effectiveness of these production processes were introduced. Hybrids created in the Maize Research Institute "Zemun Polje" represent unique starting material for research of the possibilities of bioethanol, starch and animal feed production. The aim of this study was to, starting from different physical properties and chemical composition of standard and specialty hybrids of different genetic background, determine how and in which level do the grain characteristics affect the yield and quality of the final products. The physical and chemical properties of grain corn hybrids were investigated. The optimization process of enzymatic hydrolysis and fermentation of whole grain flour obtained from the selected maize hybrids by using thermostable enzyme α-amylase Termamyl SC and glucoamylase SAN Extra L, as well as the production microorganism - yeast Saccharomyces cerevisiae var. ellipso

BACKGROUND: Bioethanol is mostly produced from starchy parts of the corn grain kernel leaving significant amounts of valuable by-products such as dried distillers' grains with solubles (DDGS) which can be used as a substitute for traditional feedstuff. The suitability of six maize hybrids from Serbia was investigated for bioethanol and DDGS production. The correlation between physical and chemical characteristics of the grain, bioethanol yield and quality of the corresponding DDGS was assessed. RESULTS: All hybrids had very different chemical composition and physical characteristics which could allow various applications. The highest bioethanol yield (94.5% of theoretical) and volumetric productivity (2.01 g l1 h1) were obtained with hybrid ZP 434 and the lowest with ZP 611k. Regarding chemical composition, all DDGS samples manifested good properties as feed components. Their protein content was higher compared to the kernel. In addition, the samples showed high digestibility and high mineral content, especially of calcium and phosphorus. CONCLUSION: A hybrid ZP 434 was selected as the most promising bioethanol producer. This property is attributed to the highest level of soft endosperm which is more susceptible to starch-hydrolysing enzymes. A high yield potential per hectare makes it the best candidate for commercial bioethanol production.

Lactic acid is a significant chemical for the food industry. Fermentative lactic acid production on wastes could significantly improve the economy and sustainability of the process. In this study, lactic acid production was performed by L. rhamnosus ATCC 7469 on a stillage from bioethanol production on waste bread. Under optimal conditions, in fed-batch fermentation lactic acid productivity of 1.80 g L-1 h-1 has been achieved with a cell number of above 109 CFU mL-1. L. rhamnosus has shown high survival rate of over 85% in the presence of beef bile and at low pH value of MRS broth. The residuals after the fermentation were chemically analyzed and their composition corresponded well with the values recommended for the feed. The digestible energy was 17452.25 kJ kg-1, while metabolisable energy was 17360.83 kJ kg-1. The high values of energy parameters indicated that an integrated process for lactic acid and feedstuff production could be a good strategy., Mlečna kiselina je važna supstanca za prehrambenu industriju. Proizvodnja mlečne kiseline fermentacijom na otpadnim sirovinama može značajno da poveća ekonomičnost i održivost procesa. U ovom radu je ispitivana proizvodnja mlečne kiseline pomoću L. rhamnosus ATCC 7469 na džibri iz proizvodnje bioetanola na otpadnom hlebu. Pod optimalnim uslovima, u dolivnom postupku je postignuta produktivnost mlečne kiseline od 1.80 g L-1 h-1 sa više od 109 CFU mL-1 bakterija. L. rhamnosus je pokazao visok stepen preživljavanja od preko 85% u prisustvu žučnih soli i pri niskoj pH vrednosti MRS bujona. Ostatak nakon mlečno-kiselinske fermentacije džibre je hemijski analiziran i pokazano je da dobijene vrednosti odgovaraju preporučenim. Svarljiva energija je iznosila 17452,25 kJ kg-1, dok je metabolička energija bila 17360,83 kJ kg-1. Visoke vrednosti energetskih parametara hraniva ukazuju da integrisani proces proizvodnje mlečne kiseline i stočne hrane na džibri predstavlja povoljnu strategiju.

In recent decades, the expansion of alternative fuels production from crops traditionally used for food and animal feed has led to significant changes in the field of energy production, agriculture and food industry. Starch and sugar feed­stocks for ethanol production (corn, wheat, sugar beet, sugar cane, etc.) require increasing arable land to meet market demands for the biofuel production. Although intensive studies are being carried out in order to identify improved and more cost-effective methods for the utilization of lignocellulosic and communal waste in the production of alcohol fuel, the possibility of using dry distillers' grains with solubles (DDGS), by-product of bioethanol production from corn and wheat as well as alcoholic beverages industry, is now in focus. Application of DDGS in livestock and poultry diets in concentrations greater than traditional could positively affect the economic viability of this biofuel production, but also stabilize the current imbalance in the food and animal feed market. However, DDGS feedstuff should not be treated as a perfect substitute for corn, because the complexity of ration formulation determined at the farm or feedlot level is driven by energy and protein and other nutrient requirements, as well as their relative costs in the ration. Nevertheless, processing of corn by wet milling provides a multitude of co-products suitable for feedstuffs, food industry, pharmaceuticals, chemistry etc. Some of the most important wet milling co-products that have their use in feed­stuffs are corn gluten feed and corn gluten meal. The use of DDGS as a substitute for traditional feed could prevent indirect land-use changes associated with bio­fuel production, and therefore preserve the environmental destruction by saving the forests and permanent pastures. The use of distiller's grains can be beneficial to biofuel growth as this is an additional, the second largest, source of income accounting of 10-20% total income. In this paper, t, Poslednjih nekoliko decenija ekspanzija proizvodnje alternativnih goriva iz biljnih sirovina, tradicionalno namenjenih ishrani, dovela je do značajnih promena na polju kako industrije energenata tako i poljoprivrede i prehrambene industrije. Skrobne i šećerne sirovine za proizvodnju bioetanola zahtevaju sve više obradivog zemljišta kako bi se ispunili zahtevi tržišta za ovim biogorivom. Trenutno je mogućnost upotrebe suve kukuruzne džibre sa rastvorenim materijama, sporednog proizvoda procesa proizvodnje bioetanola iz kukuruza kao i alkoholnih pića u žiži interesovanja. Njena primena u smešama za ishranu domaćih životinja, u koncentracijama većim od onih koje su do sada praktikovane, mogla bi pozitivno da utiče na ekonomsku isplativost proizvodnje ovog goriva, ali i da stabilizuje trenutno narušenu ravnotežu na tržištu prehrambenih proizvoda. U ovom radu prikazane su mogućnosti primene sporednih proizvoda iz proizvodnje bioetanola i industrije alkoholnih pića iz kukuruznog zrna. Akcenat je stavljen na suvu kukuruznu džibru sa rastvorenim materijama koja je procentualno najzastupljeniji i za istraživače trenutno najatraktivniji sporedni proizvod industrije bioetanola.

Lactic acid is a significant chemical for the food industry. Fermentative lactic acid production on wastes could significantly improve the economy and sustainability of the process. In this study, lactic acid production was performed by L. rhamnosus ATCC 7469 on a stillage from bioethanol production on waste bread. Under optimal conditions, in fed-batch fermentation lactic acid productivity of 1.80 g L-1 h-1 has been achieved with a cell number of above 109 CFU mL-1. L. rhamnosus has shown high survival rate of over 85% in the presence of beef bile and at low pH value of MRS broth. The residuals after the fermentation were chemically analyzed and their composition corresponded well with the values recommended for the feed. The digestible energy was 17452.25 kJ kg-1, while metabolisable energy was 17360.83 kJ kg-1. The high values of energy parameters indicated that an integrated process for lactic acid and feedstuff production could be a good strategy., Mlečna kiselina je važna supstanca za prehrambenu industriju. Proizvodnja mlečne kiseline fermentacijom na otpadnim sirovinama može značajno da poveća ekonomičnost i održivost procesa. U ovom radu je ispitivana proizvodnja mlečne kiseline pomoću L. rhamnosus ATCC 7469 na džibri iz proizvodnje bioetanola na otpadnom hlebu. Pod optimalnim uslovima, u dolivnom postupku je postignuta produktivnost mlečne kiseline od 1.80 g L-1 h-1 sa više od 109 CFU mL-1 bakterija. L. rhamnosus je pokazao visok stepen preživljavanja od preko 85% u prisustvu žučnih soli i pri niskoj pH vrednosti MRS bujona. Ostatak nakon mlečno-kiselinske fermentacije džibre je hemijski analiziran i pokazano je da dobijene vrednosti odgovaraju preporučenim. Svarljiva energija je iznosila 17452,25 kJ kg-1, dok je metabolička energija bila 17360,83 kJ kg-1. Visoke vrednosti energetskih parametara hraniva ukazuju da integrisani proces proizvodnje mlečne kiseline i stočne hrane na džibri predstavlja povoljnu strategiju.

The rapid depletion of the world petroleum supply and the increasing problem of greenhouse gas effects have strengthened the worldwide interest in alternative, nonpetroleum sources of energy. Bioethanol accounts for the majority of biofuel use worldwide, either as a fuel or a gasoline enhancer. Utilization of bioethanol can significantly reduce petroleum use and exhaust greenhouse gas emission. The production of this fuel has been increasing over the years, and has reached the level of 73.9 billion liters during the year 2009. Even though for decades ethanol production mainly depended on energy crops containing starch and sugar (corn, sugar cane etc.), new technologies for converting lignocellulosic biomass into ethanol are under development today. The use of lignocellulosic biomass, such as agricultural residues, forest and municipial waste, for the production of biofuels will be unavoidable if liquid fossil fuels are to be replaced by renewable and sustainable alternatives. For biological conversion of lignocellulosic biomass, pretreatment plays a central role affecting all unit operations in the process and is also an important cost deterrent to the commercial viability of the process. The key obstacles are: pretreatment selection and optimization; decreasing the cost of the enzymatic hydrolysis; maximizing the conversion of sugars (including pentoses) to ethanol; process scale-up and integration to minimize energy and water demand; characterization and evaluation of the lignin co-product; and lastly, the use of the representative and reliable data for cost estimation, and the determination of environmental and socio-economic impacts. Currently, not all pretreatments are capable of producing biomass that can be converted to sugars in high enough yield and concentration, while being economically viable. For the three main types of feedstocks, the development of effective continuous fermentation technologies with near to 100% yields and elevated volumetric producti, Bioetanol je biogorivo koje se širom sveta koristi kao zamena za fosilna goriva. Upotrebom smeša bioetanola i benzina može se znatno smanjiti potreba za naftom kao i emisija gasova staklene bašte, odnosno zagađenje životne sredine. Iako se bioetanol već decenijama proizvodi iz skrobnih i šećernih sirovina, useva namenjenih prvenstveno ishrani, danas se smatra da korišćenje obradivih poljoprivrednih površina za proizvodnju ovog goriva nije opravdano pa se intenzivno razvijaju tehnologije za njegovo dobijanje iz lignoceluloznih izvora biomase kao što su šumski, poljoprivredni i komunalni otpad. Upotreba lignocelulozne biomase za proizvodnju biogoriva biće neizbežna u bližoj budućnosti kada se očekuje da će se tečna fosilna goriva morati zameniti obnovljivim održivim alternativama. Primena novih enzimskih sistema za hidrolizu celuloze, sinteza fermentativnih sojeva tolerantnih na inhibitore koji fermentišu pentozu, u kombinaciji sa optimizovanom integracijom procesa, obećavaju značajan napredak.

The suitability of selected ZP maize hybrids for bioethanol and starch production was studied. The composition, physical and chemical traits, and the alcoholic fermentation of the maize hybrids hydrolysates were studied using Saccharomyces cerevisiae var. ellipsoideus yeast. The hybrid ZP 434 achieved the highest ethanol yield of 90.2% of the theoretical yield after 34 hr of fermentation, the maximum yield of 65.16%, and starch recovery of 93.14%. The hybrid ZP 544 obtained the lowest ethanol yield of 69.32%. The similar ethanol yield (approximately 79%) was also detected in Hybrids ZP 704wx and ZP 341 obtained similar ethanol yield of ≈ 79%, but differed very much on their starch content. The highest (74.13%) and the lowest (69%) starch contents were determined in hybrids ZP 704wx and ZP 341, respectively. This is an abstract of a paper presented at the 19th International Congress of Chemical and Process Engineering and 7th European Congress of Chemical Engineering (Prague, Czech Republic 8/28/2010-9/1/2010).