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The underutilized biomass and different organic waste streams are nowadays in the focus of research for renewable energy production due to the effusive use of fossil fuels and greenhouse gas emission. In addition, one of the major environmental problems is also a constant increase of the number of organic waste streams. In a lot of countries, sustainable waste management, including waste prevention and reduction, has become a priority as a means to reduce pollution and greenhouse gas emission. Application of biogas technology is one of the promising methods to provide solutions for both actual energy-related and environmental problems. This review aims to present conventional and novel biogas production systems, as well as purification and upgrading technologies, nowadays applicable on a large scale, with a special focus on the CO2 and H2S removal. It also gives an overview of feedstock and the parameters important for biogas production, together with digestate utilization and application of molecular biology in order to improve the biogas production., Nedovoljno iskorištena biomasa i različiti tokovi organskog otpada su u današnje vrijeme u fokusu istraživanja proizvodnje obnovljive energije, zbog raširene upotrebe fosilnih goriva i emisije stakleničkih plinova. Osim toga, jedan od glavnih ekoloških problema je stalno povećanje broja tokova organskog otpada. U mnogim je zemljama održivo gospodarenje otpadom, uključujući prevenciju i smanjenje otpada, postalo prioritet radi smanjenja onečišćenja okoliša i emisije stakleničkih plinova. Primjena tehnologije proizvodnje bioplina jedna je od obećavajućih metoda traženja rješenja za aktualne energetske i ekološke probleme. Svrha je ovog preglednog rada bila prikazati konvencionalne i nove sustave za proizvodnju bioplina te tehnologije pročišćavanja i obogaćivanja bioplina, koje se danas primjenjuju u velikom mjerilu, s posebnim naglaskom na uklanjanje CO2 i H2S. Ovaj rad također daje pregled sirovina i parametara važnih za proizvodnju bioplina, kao i podataka o korištenju digestata i primjeni molekularne biologije za poboljšanje proizvodnje bioplina.

This study aimed at the exploitation of lignocellulosic wastes for the evaluation of the newly isolated white-rot fungal strains enzymatic potential for bioethanol production. The isolates belonging to Basidiomycetes, Fomes fomentarius TMF2, Schizophyllum commune TMF3, and Bjerkandera adusta TMF1, could synthesize extracellular laccase and various hydrolase while growing on lignocellulosic waste materials. More specifically, for the first time, F. fomentarius TMF2 synthesized laccase using sunflower meal as a substrate. This substrate could stimulate B. adusta TMF1 for carboxymethyl cellulase and Avicelase production. The isolate B. adusta TMF1 was able to produce amylase during its growth on brewerʼs spent grain, which is up to now the best result reported for this activity of any B. adusta strain. Soybean meal was the most potent substrate for stimulating pectinase production by B. adusta TMF1 and S. commune TMF3. While growing on brewerʼs spent grain, B. adusta TMF1 and S. commune TMF3 produced high levels of xylanase. Spent coffee residues were for the first time tested as a substrate for hydrolase production by selected fungal species. Also, this is the first attempt where the produced enzymes by isolate B. adusta TMF1 were used for lignocellulose hydrolysis of brewerʼs spent grain and corn stover for bioethanol production, where under non- optimized conditions 0.94 g/L and 0.86 g/L of bioethanol could be produced, respectively. This study showed that novel white-rot fungal isolates, especially B. adusta TMF1, could grow on unexploited, low-cost lignocellulosic substrates and to produce biotechnological value-added products within environmental and economical accepted processes.

Purpose This study aimed in exploitation of lignocellulosic wastes for the evaluation of the newly isolated white-rot fungal strains enzymatic potential, covered by the circular economy frame.Methods A standard microbiological methods for the isolation of the white-rot fungal mycelia were used, followed by DNA extraction, PCR amplification, and the API ZYM test. The determination of laccase activity was based on the oxidation of guaiacol while the DNS method was used for the hydrolase determination.Results The isolates, belonged to Basidiomycetes, Fomes fomentraius TMF2, Schizophyllum commune TMF3, and Bjerkandera adusta TMF1, could synthesize extracellular laccase and various hydrolase while growing on lignocellulosic waste materials. More specifically, for the first time, F. fomentarius TMF2 synthesized laccase using sunflower meal as a substrate. This substrate could stimulate B. adusta TMF1 for Carboxymethyl cellulase and Avicelase production. The strain TMF1 was able to produce amylase during its growth on brewerʼs spent grain, which is up to now the best result reported for this activity of any B. adusta strain. Soybean meal was the most potent substrate for stimulating pectinase production by TMF1 and S. commune TMF3. While growing on brewerʼs spent grain, TMF1 and TMF3 strains produced high levels of xylanase. Spent coffee residues were for the first time tested as a substrate for hydrolase production by selected fungal species.Conclusion The obtained results showed that newly isolates of white-rot fungi can grow on unexploited lignocellulosic waste materials to produce different enzymes as a value-added products suitable for various biotechnological applications.

Microbial lipids have similar fatty acid composition to plant oils, and therefore, are considered as an alternative feedstock for biodiesel production. Oleaginous yeasts accumulate considerable amounts of lipids intracellularly during growth on low-cost renewable feedstocks such as lignocellulosic biomass. In this study, we cultivated yeast Trichosporon oleaginosus on hydrolysate of alkaline pretreated corn cobs. Different process configurations were evaluated and compared, including separate hydrolysis and fermentation (SHF) with cellulase recycle and simultaneous saccharification and fermentation (SSF) in batch and fed-batch mode. At low enzyme loading, the highest lipid concentration of 26.74 g L−1 was reached in fed-batch SSF fed with 2.5% (g g−1) substrate. Batch SHF was conducted for four rounds with recycling the cellulase adsorbed on unhydrolyzed lignocellulosic biomass. Thirty percent of cellulase saving was achieved for rounds 2–4 without compromising productivity and lipid yield. The addition of Tween 80 to lignocellulosic slurry improved the hydrolysis rate of structural carbohydrates in pretreated lignocellulosic biomass. Furthermore, supplementing the growth medium with Tween 80 improved lipid yield and productivity without affecting yeast growth. Oleaginous yeast T. oleaginosus is a promising strain for the sustainable and efficient production of lipids from renewable lignocellulosic feedstock.

High production costs of microbial lipids can be reduced by using available and cheap lignocellulosic biomass. The present study optimizes the cultivation conditions of oleaginous fungus Mortierella isabellina and lipid production in corn cobs hydrolysate regarding initial carbon to nitrogen ratio (C:N) in the growth medium, a pretreatment method and, inoculum type. Additionally, we studied the effect of the most abundant lignocellulose-derived inhibitors on lipid synthesis and fungus growth. Low C:N ratios from 5 to 25 mol mol−1 stimulated the fungus growth, while C:N ratios above 50 mol mol−1 gave rise to lipid accumulation. Corn cobs were subjected to dilute acid and alkali pretreatment, using 0.369 g of sulphuric acid and 0.16 g of sodium hydroxide per gram of lignocellulosic biomass, respectively. Growth media based on hydrolysate of alkaline pretreated corn cobs has proved suitable for growth and lipid production. Lipid yield and lipid concentration was 0.13 g g−1 and 8.40 g L−1, respectively. The most toxic inhibitors generated during pretreatment were phenolics, followed by furan aldehydes and aliphatic acids. Using vegetative mycelium instead of spores as inoculum helped cells to overcome the inhibition effect by 5-hydroxymethylfurfural and furan.

Ovo istraživanje namijenjeno je određivanju prosječnog kemijskog sastava, udjela bioaktivnih spojeva i antioksidacijske aktivnosti jestivih samoniklih gljiva Albarellus per-caprae i Armilaria mellea. Rezultati određivanja kemijskog sastava su pokazali da su gljive bogat izvor bjelančevina i ugljikohidrata te da imaju male količine masti, a dobar su izvor energije. Koncentracije pet bioaktivnih spojeva (askorbinska kiselina, β-karoten, likopen, ukupni fenoli i flavonoidi) određene su ekstrakcijom plodišta gljiva u vrućoj vodi i metanolu. Tri komplementarna kemijska ispitivanja; reducirajuća snaga, uklanjanje slobodnih radikala (DPPH) i sposobnost keliranja iona željeza korišteni su za određivanje antioksidacijskih svojstava ekstrakata. Najveće vrijednosti antioksidacijskog kapaciteta određene su u ekstraktima A. mellea s vrućom vodom (9,01 μM TE/g s.tv. u reducirajućoj snazi, 65% u sposobnosti uklanjanja slobodnih radikala, i 85% u sposobnosti keliranja). Vrijednosti EC50 za tri različita ispitivanja antioksidanta bile su između 1,63 mg/ mL i 6,86 mg/mL. Zbog ovih karakteristika, jestive samonikle gljive A. per-caprae i A. mellea mogu biti dio dobro uravnotežene prehrane i izvor bioaktivnih sastojaka., This study is designed for the determination of proximate chemical composition, contents of bioactive compounds, and antioxidant activity of wild edible mushrooms Albarellus per-caprae and Armilaria mellea. The obtained results of chemical composition revealed that the mushrooms were rich source of proteins and carbohydrates, low in fat content, and provides a good source of energy. Concentrations of five bioactive compounds (ascorbic acid, β-carotene, lykopene, total phenols, and flavonoids) are determined in hot water and methanolic extracts of mushrooms fruit bodies. Three complementary chemical assays: reducing power, free radical scavenging (DPPH), and chelating ability for ferrous ions were used to screen the antioxidant properties of extracts. The highest antioxidant capacity values were found for hot water extracts of A. mellea (9.01 μM TE/g d.w. in reducing power, 65% in scavenging ability, and 85% in chelating ability). EC50 values for three different antioxidant assays were between 1.63 mg/mL to 6.86 mg/mL. Due to these characteristics, wild edible mushrooms A. per-caprae and A. mellea could be used in well-balanced diets and as a source of bioactive compounds.

Bakterijska nanoceluloza (BNC) je obnovljiva prirodna polimerna sirovina koju karakteriziraju izvrsna svojstva poput visoke kristaliničnosti i stupnja polimerizacije, hidrofilnosti, kiralnosti, biorazgradivosti, te sposobnosti stvaranja različitih morfologija polukristaliničnih vlakana. U ovom je radu istraživan uzgoj kombuche u aerobnim uvjetima tijekom 14 dana fermentacije u kokosovoj vodi na sobnoj temperaturi, pri različitim koncentracijama saharoze. Praćene su promjene pH vrijednosti, koncentracije etanola, octene, glukonske i mliječne kiseline, kao i prinos BNC. Istraživana je kinetika otpuštanja vode iz sintetizirane BNC, a rezultati su potvrdili da su uzorci pogodni za zacjeljivanje rana na koži. Antimikrobna aktivnost kombuche je testirana na bakterijama Escherichia coli, Staphylococcus aureus, Salmonella typhimurium i Bacillus subtilis, te kvascu vrste Candida albicans. Uočena je antimikrobna aktivnost fermentirane kokosove vode na bakterije, no ne u potpunosti i na kvasac C. albicans., Bacterial nanoellulose (BNC) is a sustainable natural polymeric raw material characterized by exciting properties such as hydrophilicity, chirality, biodegradability, broad chemical-modifying capacity, and the formation of different semicrystalline fiber morphologies. This work studies cultivation of kombucha in aerobic conditions over a period up to 14 days of fermentation in coconut water, at room temperature with different sucrose concentrations added. Changes in pH value, ethanol, acetic acid, gluconic acid, and lactic acid concentrations were observed, as well as yield of BNC. The water release rate (WRR) were investigated, and the results supported its anticipated use as antimicrobial wound dressing material. The antimicrobial activity of kombucha was tested against bacteria Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Bacillus subtilis, as well as yeast Candida albicans. Antimicrobial activitiy of coconut water was observed in the fermented samples against all the investigated bacteria strains, but not completely against yeast Candida albicans.

Bioetanol je proizveden procesom istodobne saharifikacije i fermentacije (eng. Simultaneous saccharification and fermentation, SSF) s kvascem Saccharomyces cerevisiae na enzimskom hidrolizatu predobrađenih kukuruznih oklasaka. Istraživan je učinak trajanja predhidrolize kukuruznih oklasaka na učinkovitost procesa proizvodnje bioetanola te je uspoređen s konvencionalnim procesom SSF. Dvije smjese komercijalno dostupnih enzima rabljene su za hidrolizu sirovine; prva je sadržavala Celluclast 1.5L (Sigma) i β-glukozidazu (Carl Roth), a druga smjesa Celluclast 1.5L (Sigma) i Viscozyme L (Sigma). Dva dana predhidrolize imala su pozitivan učinak na prinos bioetanola, dok je dulje trajanje predhidrolize smanjilo prinos bioetanola. Najveća koncentracija etanola od 41,24 g dm–3 postignuta je u procesu SSF uz dva dana predhidrolize koja je iznosila 63,15 % teoretskog iskorištenja izračunatog na neobrađeni kukuruzni oklasak. Najveća ukupna produktivnost procesa od 0,36 g dm–3 h–1 postignuta je konvencionalnim SSF-om uz enzimsku smjesu koja je sadržavala Celluclast 1.5L (Sigma) i Viscozyme L (Sigma). Koncentracija etanola iznosila je 36,6 g dm–3, što je 56,02 % teoretskog prinosa etanola na neobrađeni kukuruzni oklasak. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna., Bioethanol was produced from cellulase-hydrolysed pretreated corn cobs by simultaneous saccharification and fermentation (SSF) with yeast Saccharomyces cerevisiae. The effect of the duration of the corn cob prehydrolysis step on ethanol yield by SSF process was studied and compared to the conventional SSF process. Two mixtures of commercially available enzyme preparations were used for biomass hydrolysis; the first contained Celluclast 1.5L (Sigma) and ß-glucosidase (Carl Roth), and the second mixture contained Celluclast 1.5L (Sigma) and Viscozyme L (Sigma). Two days of prehydrolysis had a positive effect on ethanol yield, while the yield decreased with longer prehydrolysis. The highest ethanol concentration of 41.24 g dm–3 was obtained by SSF process with two days of prehydrolysis, which corresponded to 63.15 % of the theoretical yield based on untreated corn cobs. However, the highest total productivity of 0.36 g dm–3 h–1 was observed in conventional SSF process using enzyme mixture containing Celluclast 1.5L (Sigma) and Viscozyme L (Sigma). Concentration of ethanol was 36.6 g dm–3 which corresponded to 56.02 % of the theoretical yield based on untreated corn cobs. This work is licensed under a Creative Commons Attribution 4.0 International License.

SUMMARY Production of biofuels from renewable feedstocks has captured considerable scientific attention since they could be used to supply energy and alternative fuels. Bioethanol is one of the most interesting biofuels due to its positive impact on the environment. Currently, it is mostly produced from sugar- and starch-containing raw materials. However, various available types of lignocellulosic biomass such as agricultural and forestry residues, and herbaceous energy crops could serve as feedstocks for the production of bioethanol, energy, heat and value-added chemicals. Lignocellulose is a complex mixture of carbohydrates that needs an efficient pretreatment to make accessible pathways to enzymes for the production of fermentable sugars, which after hydrolysis are fermented into ethanol. Despite technical and economic difficulties, renewable lignocellulosic raw materials represent low-cost feedstocks that do not compete with the food and feed chain, thereby stimulating the sustainability. Different bioprocess operational modes were developed for bioethanol production from renewable raw materials. Furthermore, alternative bioethanol separation and purification processes have also been intensively developed. This paper deals with recent trends in the bioethanol production as a fuel from different renewable raw materials as well as with its separation and purification processes.

Microalgae have been recognized as powerful phototrophic cell-factories whose applications range from biomass production for food and feed purposes to the production of high-value products and biofuels. Microalgae have been considered a source of functional ingredients, such as polyunsaturated fatty acids, polysaccharides, essential minerals, vitamins and bioactive peptides that can have positive effects on human and animal health. Besides having high nutritional value due to the high percentage of proteins in their composition, microalgae generate high-value products, such as pigments, polysaccharides, bio-hydrogen, and even bio-polyesters with plastic-like properties. Algal biomass that remains after product recovery can be used as forage, biofertilizer or feedstock for biogas production. This step in overall algal production is important from an economic point of view due to the reduction in production costs. This paper presents the detailed study of the biotechnologically most important microalgae strains, and the design principles of photobioreactors for their cultivation. In addition, the main existing and potential high-value products derivable from microalgae, as well as utilization of microalgae for phytoremediation and biogas production, were reviewed. This work is licensed under a Creative Commons Attribution 4.0 International License.

BACKGROUND Biodiesel is an alternative to conventional fossil diesel fuel. Currently, it is mainly produced from vegetable oils and consequently it has an adverse impact on food price. Lipids from oleaginous microorganisms (e.g. microalgae, bacteria, fungi and yeasts) could be an alternative feedstock for biodiesel production and therefore the growth and lipid accumulation of Trichosporon oleaginosus was studied under different conditions. RESULTS The growth of T. oleaginosus on the xylose containing media enhanced the lipid accumulation and reduced cell growth, while on the glucose-containing media the opposite effect was observed. Trichosporon oleaginosus can accumulate above 50% of total lipids in dry cell mass during continuous and batch culture in the nitrogen-limited conditions. In the continuous culture relatively high productivity of total lipid accumulation (0.67 g dm−3 h−1) was observed on the glucose containing media. The type of substrate limitation has considerable impact on the fatty acid composition of yeast cell lipids. The predicted biodiesel properties (based on the fatty acids composition of lipids) were found to meet the CEN quality standards. CONCLUSION The results obtained show that T. oleaginosus has great potential for feasible biodiesel production, especially when sugars from industrial and agricultural waste are used as a substrate. © 2016 Society of Chemical Industry

Povećanje emisije stakleničkih plinova, energetska ovisnost i nestabilnost isporuke energenata posljedica su ubrzane potrošnje fosilnih goriva zbog ubrzanog rasta svjetske populacije i industrijalizacije. Bioetanol je postao atraktivno zamjensko biogorivo jer se proizvodi iz obnovljivih sirovina i ekološki je prihvatljiv. Upotrebljava se kao pogonsko gorivo i to kao hidrirani (96 %) ili bezvodni (u mješavinama s benzinom). Bioetanol se proizvodi fermentacijom s kvascem S. cerevisiae ili nekim drugim mikroorganizmom iz ugljikohidrata kao što su jednostavni šećeri, škrob i celuloza. Nakon fermentacije, bioetanol se izdvaja i pročišćava destilacijom i dehidracijom. Sastav je propisan specifikacijama za primjenu u motornim gorivima. Uobičajeni usjevi, kao što su kukuruz, šećerna repa i trska, zasad su osnovne sirovine za proizvodnju bioetanola. Međutim, proizvodnja bioetanola iz ovih sirovina ne može zadovoljiti globalne potrebe za bioetanolom, zbog njihove primarne uloge u prehrani ljudi i životinja. Lignoceluloza je pogodna sirovina za proizvodnju bioetanola jer je široko rasprostranjena, obnovljiva i ne upotrebljava se u prehrani. Proizvodnja bioetanola iz lignoceluloznih sirovina je složen proces, koji se u mnogim aspektima razlikuje od proizvodnje iz šećernih ili škrobnih sirovina. U ovom radu prikazane su dosadašnje i nove tehnologije u proizvodnji bioetanola uključujući primjenu različitih sirovina, postupaka proizvodnje i radnih mikroorganizama. Nadalje, navedene su mogućnosti integracije osnovnih koraka u bioprocesima proizvodnje s ciljem povećanja produktivnosti i smanjenja troškova proizvodnje.

Biodiesel is still mainly produced from different vegetable (e.g., rapeseed, palm, soybean, sunflower, and used cooking oils) oils and animal fats, and therefore it has a negative impact on food and feed prices. For biodiesel production as an alternative feedstock, lipids from oleaginous microorganisms could be used. One of the oleaginous microorganisms is yeast Trichosporon oleaginosus that has the capacity to grow and accumulate lipids on different lignocellulosic hydrolysates. In this study, corn cobs were pretreated by alkali at loading from 0.08 to 1.6 g/g dry weight of untreated (raw) corn cobs (g NaOH/gDW_UCC) at 121 °C for 30 min. In a further step, alkaline pretreated corn cobs were subjected to the enzymatic hydrolysis by using commercial multienzymes mixtures. The optimal alkali loading (0.16 g/gDW_UCC) was related to the highest glucose and xylose yields which were observed during enzymatic hydrolysis of substrate. In this study, T. oleaginosus was applied for lipid production on the enzymatic corn cobs hydrolysates by following bioprocess configurations: separate hydrolysis and lipid production (SHLP) and simultaneous saccharification and lipid production (SSLP). The SSLP was characterized by higher lipid yield (88.88 mg/gDW_UCC) and productivity (2.4 g/(L day)) as well as significant bioprocess time reduction. On the basis of the above-mentioned facts, it is obvious that SSLP with T. oleaginosus has great potential for application in industrial scale.

Biodizel i bioplin dva su vrlo važna izvora obnovljive energije širom svijeta, a posebice u zemljama EU. Biodizel se gotovo isključivo koristi kao transportno gorivo, dok se bioplin uglavnom koristi za proizvodnju električne energije i topline. Primjena sofisticiranijih tehnika pročišćavanja u proizvodnji čistog biometana iz bioplina omogućuje njegovo uvođenje u mrežu prirodnog plina i daljnju uporabu kao transportno gorivo. Dok se bioplin uglavnom proizvodi od otpadnih materijala (materijal s odlagališta otpada, gnojivo, talog zaostao pročišćavanjem otpadnih voda, poljoprivredni otpad), biodizel se u EU uglavnom dobiva iz repice ili drugih uljarica koje se koriste kao hrana, što dovodi u pitanje njihovu ulogu kao hrane ili goriva. Kako bi se ublažio ovaj problem, napravljeni su značajni napori u korištenju neprehrambenih sirovina za proizvodnju biodizela. To uključuje sve vrste otpadnih ulja i masti, no od nedavno se više pažnje posvećuje proizvodnji mikrobnih ulja uzgojem mikroorganizama koji mogu akumulirati velike količine lipida u biomasi. Obećavajući kandidati za mikrobnu proizvodnju lipida mogu se pronaći među različitim sojevima filamentoznih plijesni, kvasaca, bakterija i mikroalgi. Sirovine od interesa su i poljoprivredni otpad bogat ugljikohidratima te različite lignocelulozne sirovine, za čiju se uporabu još uvijek moraju riješiti neka tehnička pitanja. Također, u ovom su radu razmatrane metode izdvajanja i pročišćavanja biodizela i bioplina., Biodiesel and biogas are two very important sources of renewable energy worldwide, and particularly in the EU countries. While biodiesel is almost exclusively used as transportation fuel, biogas is mostly used for production of electricity and heat. The application of more sophisticated purification techniques in production of pure biomethane from biogas allows its delivery to natural gas grid and its subsequent use as transportation fuel. While biogas is produced mostly from waste materials (landfills, manure, sludge from wastewater treatment, agricultural waste), biodiesel in the EU is mostly produced from rapeseed or other oil crops that are used as food, which raises the ‘food or fuel’ concerns. To mitigate this problem, considerable efforts have been made to use non-food feedstock for biodiesel production. These include all kinds of waste oils and fats, but recently more attention has been devoted to production of microbial oils by cultivation of microorganisms that are able to accumulate high amounts of lipids in their biomass. Promising candidates for microbial lipid production can be found among different strains of filamentous fungi, yeast, bacteria and microalgae. Feedstocks of interest are agricultural waste rich in carbohydrates as well as different lignocellulosic raw materials where some technical issues have to be resolved. In this work, recovery and purification of biodiesel and biogas are also considered.

In this research, the impact of chemical agents on the growth of Euglena gracilis and contaminants (S. cerevisiae and B. subtilis) in different cultivation media was studied. E. gracilis was cultivated on modified Hutner and complex medium in Erlenmeyer flasks and a stirred tank bioreactor. H2O2 and antimycin were used as suppressors of contaminant growth activities during algae cultivation. The use of antimycin as a chemical suppressor of contaminants is not recommendable because of its significant impact on the E. gracilis growth. At a H2O2 concentration of 5 mg L-1 contaminant growth activities were almost completely suppressed. In these conditions, E. gracilis is capable to grow, but a further increase of H2O2 concentration is related to significant reduction of algae growth. H2O2 as a suppressor of contaminants has great potential for industrial application, but its optimal concentration for a particular bioprocess has to be determined in order to obtain the maximal bioprocess efficiency.

The current industrial production of the biodiesel relies mainly on vegetable oils that could result in the shortage of edible oils in food markets and increase in their prices. Microbial lipids produced by oleaginous microorganism have attracted a lot of attention in the recent years as a source of high-value polyunsaturated acids as well as alternative feedstock for the production of biodiesel. However, the production of microbial oils faces a number of problems concerning the costs of lipid extraction, carbon source and operational cost for microbial cultivation in conventional stirred tank bioreactor which makes production economically unfeasible. Non-food feedstocks, lignocellulose biomass and different waste streams containing lignocellulose, are low-cost sources of renewable carbon that could significantly reduce the production cost of microbial lipids. This review analyses the current production of microbial lipids from lignocellulose feedstocks and gives an overview of the main stages in the process of lipid production, pretreatment and hydrolysis of the feedstock and microbial cultivation. Cultivation of oleaginous microorganisms has been conducted by submerged cultivation and solid state fermentation. Three process configurations have been used in the lipid production including, separate hydrolysis and lipid production (SHLP), simultaneous saccharification and lipid production (SSLP) and consolidate bioprocessing (CBP). Implementing the biorefinery concept that includes co-production of different value-added products (polyunsaturated fatty acids, amino acids, lignin and pigments) could improve the feasibility of lipid production bioprocess.

Fossil fuels are still major energy sources, but the search for renewable energy sources has been encouraged. Bioethanol has been recognized as an alternative to fossil fuels and nowadays it represents more than 90% of the global biofuel production. Bioethanol production from raw sugar beet cossettes as a semi-solid substrate was studied. The study was carried out in the horizontal rotating tubular bioreactor (HRTB) with Saccharomyces cerevisiae as a microbial production strain. The impact of different combinations of HRTB operational parameters such as, rotation speed (5-15 min(-1)), rotation type [constant or interval (3-15 min h(-1))] and working volume (ratio V (W)/V (T) = 0.2-0.7) on the bioethanol production was examined. In this study, the highest bioprocess efficiency parameters ( = 0.47 g g(-1), E = 87.36% and Pr = 0.618 g L-1 h(-1)) were observed at 0.20 V (W)/V (T), interval rotation of 12 min h(-1) and rotation speed of 15 min(-1). It has to be pointed out that bioethanol production efficiency in the HRTB was on the similar level as observed by bioethanol production from the raw sugar beet juice. Naturally present microorganisms of sugar beet could have a significant impact on bioethanol production. Higher yeast inoculation rate could reduce contaminant activities and, consequently, the bioethanol production efficiency would be improved.

U ovom istraživanju provedeno je ispitivanje utjecaja ukupne koncentracije kisika u staklenoj boci na kakvoću piva donjeg vrenja tijekom skladištenja. Pivo je bilo skladišteno na temperaturi od 22 - 25°C u tamnoj prostoriji, a u pivu je bio prisutan kisik u tri različite ukupne početne koncentracije: 0,09 mg/L, 0,29 mg/L i 0,63 mg/L. Tijekom skladištenja (98 dana) u pivu je praćena promjena koncentracije trans-2-nonenala kao indikatora procesa oksidacije (starenja) piva, a dobiveni rezultati pokazuju da koncentracija trans-2-nonenala nije direktno ovisna o ukupnoj koncentraciji kisika u boci piva. U ovom istraživanju provedena je i senzorska analiza uzoraka piva koja je pokazala da povećane ukupne koncentracije kisika u boci izravno utječu na ocjenu kakvoće piva., In this research the effect of total packaging oxygen on the quality of bottled (glass bottle) lager beer during storage was studied. The beer was stored in a dark room at temperature of 22 - 25°C and it contained three different concentrations of total packaging oxygen: 0,09, 0,29 and 0,63 mg/L. During the 98 days storage period the concentration of trans-2-nonenal, a well known indicator of oxidation processes in the beer, was monitored. The results obtained in this research clearly show that the concentration of trans-2-nonenal is not directly related to the total oxygen concentration in the bottled beer. Sensory analysis of beer was also performed and obtained results clearly show that higher concentrations of total packaging oxygen directly effects beer quality and flavour.

In this study, different bioethanol production processes from sugar beet were analyzed to improve energy input/output ratio and process sustainability. As inputs for fermentative bioethanol production, sugar factory can use some intermediate products [e.g. raw sugar juice (≈15–18% sugar) or concentrated sugar syrup (≈65–67% sugar)] or by-products (e.g. molasses ≈50% sugar). From energetic point of view, the main energy consumption operations in bioethanol production are: sugar extraction from sugar beet chips, sugar juice concentration by evaporation, ethanol distillation as well as distillers mash concentration and beet chips drying. In decision-making processes for different bioethanol production processes from sugar beet the concept of ecological footprint was used. Results of ecological footprint pointed out that energy demand and sustainability of standard process can be significantly improved by introduction of new technologies, i.e. simultaneous sugar extraction, pulp fermentation and product recovery (SEFPR) combined with biogas production from fermentation residues.