Application of Mixed Microbial Culture Biofilms for Manganese (II), Cobalt (II), and Chromium (VI) Biosorption by Horizontal Rotating Tubular Bioreactor

Industrial wastewater contaminated with toxic heavy metals is a big ecological and environmental problem. Applying biological materials to effectively remove and recover heavy metals from contaminated wastewaters has gained importance as promising alternative to conventional treatment techniques. Thus, the objective of the presented paper is the investigation of the capability of microorganisms, isolated from polluted (metal-laden) soil, to biosorb toxic metals from aqueous solutions. Biosorption process for heavy metal removal was conducted in a new pilot scale horizontal rotating tubular bioreactor (HRTB). This bioreactor provides conditions for microorganism’s growth in a form of suspended cells and biofilm. Biofilm is capable to protect microorganisms from interaction with toxic metals in the surrounding environment. Three metals were selected as model examples: cations of manganese and cobalt and hexavalent chromium (an oxyanion). Optimized bioreactor conditions, namely, medium inflow rate (F) and bioreactor rotation speed (n) for biofilm formation and metal removal were monitored, and under optimized bioreactor conditions, promising results were obtained

Photo-mixotrophic Cultivation of Algae Euglena gracilis for Lipid Production

In the future, due to limited resources, a crisis of energy storing molecules (fuels), which are currently produced from crude mineral oil, is expected. One strategy to compensate a part of the oil deficiency is the production of biodiesel from microalgal lipids. As model microorganism for lipid production microalgae Euglena gracilis was selected and photo mixotrophic cultivation was performed in the stirred tank photobioreactor. During this research, medium composition and operational conditions of photo-bioreactor were optimized in order to define adequate cultivation conditions for algae biomass and lipid production. As low-cost and available complex carbon/ nitrogen source, corn steep liquor (CSL) was used to promote E. gracilis growth and lipid production. Due to the optimization of medium composition and cultivation conditions, lipid production was increased up to 29% of biomass dry weight in a two stage cultivation process inside one photo-bioreactor. Promising results obtained in this research encouraged us for further investigation

Primjena metode odzivnih površina u optimizaciji parametara procesa biološke obrade otpadnih voda u bioreaktoru s mikrobnim biofilmom

Cilj ovog rada je bio optimizirati parametre procesa biološke obrade otpadnih voda te odrediti njihov utjecaj na odvijanje procesa pomoću metode odzivnih površina. Bioproces simultane nitrifikacije i denitrifikacije je proveden u horizontalnom rotirajućem cijevnom bioreaktoru (HRCB) s biofilmom mikroorganizma Paracoccus denitrificans. Podaci dobiveni eksperimentom su obrađivani statističkim metodama linearne regresije i višesmjerne analize varijance. Utvrđene su kritične vrijednosti za brzinu protoka hranjive podloge (0,6 L/h) te brzinu rotacije bioreaktora (16,9 min-1). Na temelju provedenog istraživanja može se zaključiti da statistički najznačajniji utjecaj na proces simultane nitrifikacije i denitrifikacije ima brzina protoka hranjive podloge

LPMO – ključni enzim u održivoj pretvorbi lignocelulozne biomase

The importance of the lytic polysaccharide monooxygenase (LPMO) enzyme in the preparation of lignocellulosic raw materials for production in biorefineries has been confirmed in numerous investigations. Therefore, LPMO enzymes were investigated to explore the enzyme-substrate interaction with the aim of successful biomass conversion in biorefinery processes. After reductive activation of LPMOs active site, they cleave the substrate and prepare it for biomass degradation by hydrolytic enzymes. In this paper, the role of LPMO in lignocellulosic biomass conversion is described based on the recent studies of: LPMO enzyme structure, LPMO substrate preferences, and the LPMO reaction mechanism. These findings are important for the selection of suitable bioprocess conditions with the aim of LPMO activation/stabilisation in biorefinery production processes.Važnost enzima litičke polisaharidne monooksigenaze (LPMO) u pripremi lignoceluloznih sirovina za proizvodnju u biorafinerijama potvrđena je u brojnim istraživanjima. Stoga su istražene i interakcije LPMO enzima i supstrata s ciljem primjene tih istraživanja u uspješnoj pretvorbi lignocelulozne biomase u biorafinerijama. Nakon redukcije aktivnog mjesta LPMO enzima dolazi do vezanja i razgradnje supstrata te pripreme za djelovanje hidrolitičkih enzima. U ovom radu opisana je uloga LPMO enzima u pretvorbi lignocelulozne biomase na temelju nedavnih istraživanja: strukture LPMO enzima, specifičnosti supstrata na koje djeluje i mehanizma reakcije. Ova istraživanja važna su za odabir prikladnih uvjeta bioprocesa s ciljem aktivacije/stabilizacije LPMO enzima tijekom proizvodnje u biorafinerijama

Primjena metode odzivnih površina u optimizaciji parametara procesa biološke obrade otpadnih voda u bioreaktoru s mikrobnim biofilmom

Cilj ovog rada je bio optimizirati parametre procesa biološke obrade otpadnih voda te odrediti njihov utjecaj na odvijanje procesa pomoću metode odzivnih površina. Bioproces simultane nitrifikacije i denitrifikacije je proveden u horizontalnom rotirajućem cijevnom bioreaktoru (HRCB) s biofilmom mikroorganizma Paracoccus denitrificans. Podaci dobiveni eksperimentom su obrađivani statističkim metodama linearne regresije i višesmjerne analize varijance. Utvrđene su kritične vrijednosti za brzinu protoka hranjive podloge (0,6 L/h) te brzinu rotacije bioreaktora (16,9 min-1). Na temelju provedenog istraživanja može se zaključiti da statistički najznačajniji utjecaj na proces simultane nitrifikacije i denitrifikacije ima brzina protoka hranjive podloge

Photo-mixotrophic Cultivation of Algae Euglena gracilis for Lipid Production

In the future, due to limited resources, a crisis of energy storing molecules (fuels), which are currently produced from crude mineral oil, is expected. One strategy to compensate a part of the oil deficiency is the production of biodiesel from microalgal lipids. As model microorganism for lipid production microalgae Euglena gracilis was selected and photo mixotrophic cultivation was performed in the stirred tank photobioreactor. During this research, medium composition and operational conditions of photo-bioreactor were optimized in order to define adequate cultivation conditions for algae biomass and lipid production. As low-cost and available complex carbon/ nitrogen source, corn steep liquor (CSL) was used to promote E. gracilis growth and lipid production. Due to the optimization of medium composition and cultivation conditions, lipid production was increased up to 29% of biomass dry weight in a two stage cultivation process inside one photo-bioreactor. Promising results obtained in this research encouraged us for further investigation

Optimisation of algae Euglena gracilis cultivation conditions for vitamin A and vitamin E production

U ovom istraživanju proveden je uzgoj alge Euglena gracilis s ciljem proizvodnje vitamina A i vitamina E. U svrhu određivanja najpovoljnijih parametara za proizvodnju vitamina u bioreaktoru s mješalom provedena je optimizacija sastava hranjive podloge i uvjeta uzgoja E. gracilis, u Erlenmeyer tikvicama na laboratorijskoj tresilici. Tijekom uzgoja alge E. gracilis u bioreaktoru s mješalom primijenjen je dvostupanjski uzgoj. U prvom stupnju proveden je fotoheterotrofni uzgoj na Hutner-ovoj podlozi, a u drugom stupnju miksotrofni uzgoj na podlozi s ograničenim izvorom ugljika. Primjena dvostupanjskog procesa osigurala je relativno visoku produktivnost proizvodnje vitamina A (PrA = 0,07 mg/Lh) i vitamina E (PrE= 0,27 mg/Lh), a prinosi su iznosili vitamina A (YA = 6,53 mg/L) odnosno vitamina E (YE = 26,26 mg/L). Visoki prinosi vitamina E ukazuju na mogućnost primjene dvostupanjskog procesa njegove proizvodnje u industrijskom mjerilu.In this research, cultivation of algae Euglena gracilis was studied in order to produce vitamin A and vitamin E. The optimization of medium composition and cultivation conditions, in Erlenmeyer flasks on laboratory shaker, was done to define the most appropriate parameters for vitamin production in the stirred tank bioreactor. During cultivation of E. gracilis in the stirred tank bioreactor two-step process was examined. In the first step photoheterotrofic cultivation on the Hutner medium was done and in the second step photomixotrophically cultivation on the limited carbon source medium. In the two step process following bioprocess efficiency parameters were observed: productivity for vitamine A (PrA = 0.07 mg/Lh) and vitamin E (PrE= 0.27 mg/Lh) production as well as vitamin A (YA = 6.53 mg/L) and vitamin E (YE = 26.26 mg/L) yield. High vitamin E yield indicate potential of two-step processes for this vitamin industrial scale production

Održivost uporabe ninskog peloida za primjenu u peloterapiji

Evolucijski gledano, znanstveni dokazi upućuju da je život nastao u pretečama vodenih ekosustava kao nakupinama toplog blata bogatog hranjivim tvarima i mineralima. Ove vrste blata, također zvane peloidi, nastaju nakupljanjem organskih tvari i njihovim miješanjem sa anorganskim tvarima iz gline. Miješanje pospješuju slatka i morska voda bogate mineralima. Nalazišta peloida su često plitke i zatvorene lagune, stalno izložene visokom UV zračenju, koncentraciji soli i temperaturi, zapravo ekstremna okruženja za život brojnih mikroorganizama. Mikroorganizmi koriste minerale iz okoliša, razlažu organske tvari, dakle ostatke biljaka i drugih makro i mikroorganizama i prilikom prilagodbe na okolišne uvjete sintetiziraju široku paletu primarnih i sekundarnih metabolita s ciljem obrane i prilagodbe na ekstremne uvjete okoliša. Na ovaj način sintetizirani metaboliti imaju brojno i raznoliko djelovanje, a svoju potencijalnu primjenu pronalaze u biotehnološkoj, kozmetičkoj i farmaceutskoj industriji. Unatoč dva tisućljeća stare i dokazane uporabe u ljekovite i medicinske svrhe, ali i jake turističke i medijske promocije, u modernom je razdoblju mali broj znanstvenika svoje znanje i sposobnost okušao u istraživanju ljekovitosti i dokazivanja dobrobiti ili pak štetnosti uporabe i terapije ninskim peloidom na ljudsko tijelo. Studija temeljena na znanstvenom istraživanju, zajedno sa sastavljanjem racionalnog i održivog plana uporabe ninskog peloida kao prirodnog resursa, bila bi temelj potencijalne komercijalizacije nalazišta i njegove primjene u medicinskoj, farmaceutskoj i biotehnološkoj industriji