New feedstocks for bioethanol production

In the last few decades raw material molasses, used in large scale fermentations in the production of bioethanol, citric acid, (baker´s) yeast and yeast extracts, has become more and more expensive. That is why agro-industrial wastes have become an interesting alternative. They are being produced in large volumes every day and represent a serious environmental problem considering its high organic content. The present contribution aims to demonstrate how waste products of wine production can be employed as substrate in bioethanol production. Cultivation of yeast and bioethanol production on molasses and grape pomace extract was studied in flasks in laboratory scale. This work should be regarded as an example of integrated sustainability which demonstrates how the waste from one industrial process is used as feedstock for another

Transformacija problematičnog vinskog otpada u vrijedan supstrat za proizvodnju pekarskog kvasca i čvrstog biogoriva: princip kružnog gospodarstva

Research background. Wine production, which is considered a major sector in food industry, often involves the use of a large amount of resources. Moreover, wine making generates a large amount of grape pomace, which is generally used for low-value applications such as fertiliser and animal feed. The aim of the present research is to explore the possibility of improving the overall sustainability of traditional winemaking. Experimental approach. A zero-waste process was developed. It includes the production of white wine and the substantial valorisation of grape pomace, which is converted into solid biofuel, tartaric acid and concentrated grape extract as feedstock for industrial baker’s yeast production. Results and conclusions. We estimate that a significant surplus of renewable energy of approx. 3 MJ/kg processed grapes can be obtained during this conversion. The suitability of grape extract as a potential substrate for industrial baker’s yeast production was evaluated and the feasibility of a partial replacement of molasses (up to 30 %) was demonstrated. Novelty and scientific contribution. We present a circular economy approach for the conversion of winery biowaste into high-value resources such as feedstock and solid biofuel.Pozadina istraživanja. Proizvodnja vina, koja se smatra važnim sektorom u prehrambenoj industriji, često uključuje korištenje velikih resursa. Osim toga, nakon proizvodnje vina zaostaju velike količine komine grožđa, koja se obično koristi za dobivanje proizvoda niske vrijednosti, poput gnojiva ili stočne hrane. Svrha je ovog znanstvenog rada bila istražiti mogućnost poboljšanja ukupne održivosti tradicionalnog postupka proizvodnje vina. Eksperimentalni pristup. U radu je razvijen postupak koji uključuje proizvodnju bijelog vina i značajnu valorizaciju komine grožđa, koja se pretvara u čvrsto biogorivo, vinsku kiselinu i koncentrirani ekstrakt grožđa kao sirovinu za industrijsku proizvodnju pekarskog kvasca. Rezultati i zaključci. Procjenjujemo da se ovom metodom može dobiti značajan višak obnovljive energije od otprilike 3 MJ/kg obrađenog grožđa tijekom postupka. Istražena je moguća uporaba ekstrakta grožđa kao potencijalne sirovine u industrijskoj proizvodnji pekarskog kvasca, te je dokazana mogućnost djelomične zamjene melase s ekstraktom grožđa (do 30 %). Novina i znanstveni doprinos. U radu predstavljamo princip kružnog gospodarstva pri pretvaranju biološkog vinskog otpada u visokovrijedne resurse, poput sirovina i čvrstog biogoriva

Production of Blackberry Wine by Microfermentation using Commercial Yeasts Fermol Rouge® and Fermol Mediterranée®

The aim of this paper was to determine the enological traits of two commercial yeasts (Fermol Rouge® and Fermol Mediterranée®) in a small scale and to evaluate the possibility of their application in commercial production of blackberry wine. Fermentation activity was monitored by measuring CO2 evolution and CO2 production rate during microfermentation of blackberry juice performed at 23°C. Blackberry wines produced by two different yeasts were analyzed in order to compare their composition differences. Fermentations were carried on to complete sugar consumption by both yeast strains. Levels of volatile acids formed by the two yeasts were significantly different and differences in concentrations of residual sugars, malic acid, lactic acid and pH-value were highly significant. There were no significant differences between concentrations of ethanol, total acids and glycerol in blackberry wines produced by both yeasts. Chemical composition of the produced blackberry wines was in accordance with the Croatian fruit wine legislation. Good fermentative properties and low potential of H2S production of both commercial yeasts could be beneficial for blackberry wine production

Lipid production by yeast Trichosporon oleaginosus on glucose and xylose under nitrogen limitation of growth

Nakupljanje lipida u oleaginoznim mikroorganizmima započinje kada je jedan nutrijent u hranjivoj podlozi utrošen (najčešćeg izvor dušika), a izvor ugljika, koji je u suvišku, troši se za sintezu triacilglicerola. U ovom istraživanju proučavana je proizvodnja lipida sa kvascem Trichosporon oleaginosus na hranjivim podlogama s glukozom i/ili ksilozom kao izvorom ugljika uz različite omjere masa izvora ugljika i dušika (C/N). Najveći udjela lipida postignut je uz omjer masa C/N od 45 g g-1. Ksiloza se pokazala pogodnijim supstratom za proizvodnju lipida nego glukoza. Tijekom rasta u podlozi s glukozom i ksilozom kvasac redoslijedno troši izvore ugljika. Kada koncentracija glukoze padne ispod 5 g L-1, kvasac počinje rasti na ksilozi. Tijekom šaržnog uzgoja s pritokom supstrata postignut je vrlo visoki udjel lipida u stanici od 64,84 %, dok je produktivnost procesa iznosila 0,227 g L-1 h-1.Lipid accumulation in oleaginous microorganisams begins when one nutrient from the medium (usually nitrogen) is exhausted but an excess of carbon is still assimilated by the cells and is converted into triacylglycerols. Production of lipid by yeast Trichosporon oleaginosus on the medium contained glucose and/or xylose as the carbon source was studied in this research. Optimum C/N ratio for lipid accumulation was 45 g g-1 with glucose as carbon source. Maximum lipid accumulation occurred in batch culture with xylose. In the medium containing glucose and xylose microogranism showed sequential utilization of substrates. When the concentration of glucose decreased below than 5 g L-1, yeast started to spend xylose as the source of carbon. Maximum lipid accumulation occurred in fed-batch culture with glucose reaching a level of 64.34 % of the biomass and productivity of 0.227 g L-1 h-1

Enzymatic analysis of blackberry wines

Kupinovo vino je popularno voćno vino koje se tradicionalno proizvodi u kontinentalnom dijelu Hrvatske. U ranijim eksperimentima provedene su mikrofermentacije kupinovog soka pomoću dvaju komercijalnih kvasaca kako bi se procijenila mogućnost njihove primjene u komercijalnoj proizvodnji kupinovih vina. Vina proizvedena komercijalnim kvascima Fermol Rouge i Fermol Mediterraneé oznacena su kao vino FR, odnosno vino FM. U ovom radu su koncentracije neprevrelih šećera u proizvedenim vinima određene kao koncentracije reducirajucih šećera, a HPLC (tekućinska kromatografija visoke djelotvornosti) je korištena za analizu etanola. Enzimskim metodama su određene koncentracije glicerola, jabučne i mliječne kiseline u kupinovim vinima proizvedenim uz primjenu spomenutih kvasaca. Oba kvasca proizvela su jednake koncentracije glicerola. U vinu FR je koncentracija jabučne kiseline bila dvostruko manja, dok je koncentracija mliječne kiseline bila dvostruko veća nego u vinu FM.Blackberry wine is a popular fruit wine and traditional product in the continental part of Croatia. Fermentations of blackberry juice were previously performed using two commercial yeasts in a small scale to evaluate possibility of their application in production of commercial blackberry wine. The wines produced using yeasts Fermol Rouge and Fermol Mediterraneé were designated as wine FR and wine FM, respectively. Concentrations of residual sugars in the produced wines were determined as reducing sugars and ethanol levels were analysed by HPLC (high-performance liquid chromatography). Enzymatic methods were applied to analyse levels of glycerol, malic acid and lactic acid. Both yeast strains produced the same glycerol concentrations. Malic acid level in wine FR was twice lower, while lactic acid concentration was twice higher in wine FR than in wine FM

Lipid production by yeast Trichosporon oleaginosus on glucose and xylose under nitrogen limitation of growth

Nakupljanje lipida u oleaginoznim mikroorganizmima započinje kada je jedan nutrijent u hranjivoj podlozi utrošen (najčešćeg izvor dušika), a izvor ugljika, koji je u suvišku, troši se za sintezu triacilglicerola. U ovom istraživanju proučavana je proizvodnja lipida sa kvascem Trichosporon oleaginosus na hranjivim podlogama s glukozom i/ili ksilozom kao izvorom ugljika uz različite omjere masa izvora ugljika i dušika (C/N). Najveći udjela lipida postignut je uz omjer masa C/N od 45 g g-1. Ksiloza se pokazala pogodnijim supstratom za proizvodnju lipida nego glukoza. Tijekom rasta u podlozi s glukozom i ksilozom kvasac redoslijedno troši izvore ugljika. Kada koncentracija glukoze padne ispod 5 g L-1, kvasac počinje rasti na ksilozi. Tijekom šaržnog uzgoja s pritokom supstrata postignut je vrlo visoki udjel lipida u stanici od 64,84 %, dok je produktivnost procesa iznosila 0,227 g L-1 h-1.Lipid accumulation in oleaginous microorganisams begins when one nutrient from the medium (usually nitrogen) is exhausted but an excess of carbon is still assimilated by the cells and is converted into triacylglycerols. Production of lipid by yeast Trichosporon oleaginosus on the medium contained glucose and/or xylose as the carbon source was studied in this research. Optimum C/N ratio for lipid accumulation was 45 g g-1 with glucose as carbon source. Maximum lipid accumulation occurred in batch culture with xylose. In the medium containing glucose and xylose microogranism showed sequential utilization of substrates. When the concentration of glucose decreased below than 5 g L-1, yeast started to spend xylose as the source of carbon. Maximum lipid accumulation occurred in fed-batch culture with glucose reaching a level of 64.34 % of the biomass and productivity of 0.227 g L-1 h-1

Enzymatic analysis of blackberry wines

Kupinovo vino je popularno voćno vino koje se tradicionalno proizvodi u kontinentalnom dijelu Hrvatske. U ranijim eksperimentima provedene su mikrofermentacije kupinovog soka pomoću dvaju komercijalnih kvasaca kako bi se procijenila mogućnost njihove primjene u komercijalnoj proizvodnji kupinovih vina. Vina proizvedena komercijalnim kvascima Fermol Rouge i Fermol Mediterraneé oznacena su kao vino FR, odnosno vino FM. U ovom radu su koncentracije neprevrelih šećera u proizvedenim vinima određene kao koncentracije reducirajucih šećera, a HPLC (tekućinska kromatografija visoke djelotvornosti) je korištena za analizu etanola. Enzimskim metodama su određene koncentracije glicerola, jabučne i mliječne kiseline u kupinovim vinima proizvedenim uz primjenu spomenutih kvasaca. Oba kvasca proizvela su jednake koncentracije glicerola. U vinu FR je koncentracija jabučne kiseline bila dvostruko manja, dok je koncentracija mliječne kiseline bila dvostruko veća nego u vinu FM.Blackberry wine is a popular fruit wine and traditional product in the continental part of Croatia. Fermentations of blackberry juice were previously performed using two commercial yeasts in a small scale to evaluate possibility of their application in production of commercial blackberry wine. The wines produced using yeasts Fermol Rouge and Fermol Mediterraneé were designated as wine FR and wine FM, respectively. Concentrations of residual sugars in the produced wines were determined as reducing sugars and ethanol levels were analysed by HPLC (high-performance liquid chromatography). Enzymatic methods were applied to analyse levels of glycerol, malic acid and lactic acid. Both yeast strains produced the same glycerol concentrations. Malic acid level in wine FR was twice lower, while lactic acid concentration was twice higher in wine FR than in wine FM

Multidisciplinary approach in industrial baker´s yeast production : from manufacture to integrated sustainability

The present study shows how industrial baker´s yeast manufacture can be turned into multipurpose bioprocess by combining multidisciplinary developments into innovative strategic concept. It demonstrates additional roles given to this manufacture; besides producing yeast, as waste discharger and as supplier of valuable biomolecules and energy

Bridging the Implementation Gap between Pomace Waste and Large-Scale Baker’s Yeast Production

The objectives set in the European Green Deal constitute the starting point of this review, which then focuses on the current implementation gap between agro-industrial wastes as resources for large-scale bioprocesses (e.g., baker’s yeast, bioethanol, citric acid, and amino acids). This review highlights the current lack of sustainability of the post-harvest processing of grapes and apples. In light of the European Green Deal, industrial biotechnology often lacks sustainability as well. We reviewed the recent progress reported in the literature to enhance the valorization of grape and apple pomace and the current failure to implement this research in technical processes. Nevertheless, selected recent papers show new perspectives to bridge this gap by establishing close collaborations between academic teams and industrial partners. As a final outcome, for the first time, we drew a circular flow diagram that connects agriculture post-harvest transformation with the industrial biotechnology and other industries through the substantial valorization of apple and grape pomace into renewable energy (solid biofuels) and sugar extracts as feedstock for large-scale bioprocesses (production of baker’s yeast industry, citric acid, bioethanol and amino acids). Finally, we discussed the requirements needed to achieve the successful bridging of the implementation gap between academic research and industrial innovation

A Batch Reverse Osmosis Process to Recover and Recycle Trivalent Chromium from Electroplating Wastewater

Electroplating generates high volumes of rinse water that is contaminated with heavy metals. This study presents an approach for direct metal recovery and recycling from simulated rinse water, made up of an electroplating electrolyte used in industry, using reverse osmosis (RO). To simulate the real industrial application, the process was examined at various permeate fluxes, ranging from 3.75 to 30 L·m−2·h−1 and hydraulic pressures up to 80 bar. Although permeance decreased significantly with increasing water recovery, rejections of up to 93.8% for boric acid, >99.9% for chromium and 99.6% for sulfate were observed. The final RO retentate contained 8.40 g/L chromium and was directly used in Hull cell electroplating tests. It was possible to deposit cold-hued chromium layers under a wide range of relevant current densities, demonstrating the reusability of the concentrate of the rinsing water obtained by RO