Potential of Microalgae for the Production of Different Biotechnological Products

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

Body Composition and Functional Abilities in Terms of the Quality of Professional Ballerinas

The objective of this research was to determine the variability of the sample of professional ballerinas in the space of characteristics of their body composition and some functional characteristics according to the requirements of their roles in ballet. The sample of examinees was comprised of 30 professional ballerinas, members of the Croatian National Theatre Ballet (15 soloists and 15 members of the corps de ballet). The data showed that the soloists were characterized by a significantly larger knee diameter, significantly lower thickness of skin folds on the trunk and the lower fat body mass percentage, as well as by greater grip strength. Aerobic capacity was only moderately more developed than in fit people who participated in physical exercising because of recreational reasons, and there were no differences between soloists and the members of the corps

Usporedba različitih tehnika proizvodnje bioetanola iz lignoceluloznih sirovina

Bioetanol proizveden iz lignoceluloznih sirovina (npr. ostaci biomase drveta i poljoprivrednih kultura) zadovoljava kriterije ekološke i društveno-političke održivosti. Međutim, troškovi proizvodnje bioetanola iz lignoceluloznih sirovina značajno su veći u odnosu na troškove proizvodnje bioetanola iz šećernih i škrobnih sirovina. Da bi se ostvarila ekonomski održiva proizvodnja bioetanola iz lignoceluloznih sirovina neophodno je razviti i primjeniti nova tehnološka rješenja. Proces proizvodnje bioetanola može se provesti pomoću različitih tehnika vođenja bioprocesa kao što su npr. odvojeni proces hidrolize lignocelulozne sirovine i fermentacija njenog hidrolizata, simulatana hidroliza i fermentacija ili konsolidirani bioprocesni sustav. Budući da se tehnika odvojene hidrolize i fermentacije već koristi u industrijskom mjerilu za daljnji razvoj procesa proizvodnje bioetanola iz lignoceluloznih sirovina najveći potencijal ima tehnika simultane hidrolize i fermentacije zbog smanjene mogućnosti pojave inhibicije supstratom (ili drugim sastojcima hidrolizata sirovina) odnosno smanjenja kapitalnih troškova bioprocesa. Kontinuirani postupak vođenja proizvodnje bioetanola dodatno povećava učinkovitost bioprocesa, te smanjuje njegove operativne troškove. Međutim, glavni nedostaci kontinuiranog postupka su povećana mogućnost kontaminacije, nastajanje i nakupljanje nepoželjnih nusproizvoda odnosno povećani kapitalni troškovi bioprocesa. U ovome radu dan je pregled različitih tehnika proizvodnje bioetanola iz lignoceluloznih sirovina, te su ti bioprocesi međusobno uspoređeni na osnovi pokazatelja uspješnosti bioprocesa

Priprava taložnog kalcijeva karbonata šaržnim i semikontinuiranim postupkom

A comparison of the physical-chemical properties of precipitated calcium carbonate (PCC), prepared by batch and semicontinuous processes, is presented. In both processes, PCC, was synthesized by carbonation of slaked lime. In the batch process the experiments were performed by varying the initial mass concentration and temperature, and the semicontinuous process was conducted by varying the initial supersaturation and temperature. Calcite was the only calcium carbonate polymorph that appeared under the experimental conditions investigated. It was found, that in the batch experiments the specific surface area and the average size of calcite particles decreased with the increase of temperature. At the same time, the increase of the initial mass concentration of slaked lime enhanced the degree of precipitate aggregation. PCC prepared by the semicontinuous process, conducted at low temperatures and high supersaturations, was of high specific surface area. By careful tuning of the semicontinuous process parameters, calcite in the form of rhombohedral, scalenohedral or nanosized spherical particles can be producedU ovom su radu uspoređena fizičko-kemijska svojstva taložnog kalcijeva karbonata (TKK) pripravljenog karbonatizacijom vapnenog mlijeka u šaržnom i semikontinuiranom reaktoru. U šaržnom su postupku varirane temperatura i početna masena koncentracija vapnenog mlijeka, dok su u semikontinuiranom mijenjani temperatura i prezasićenost sustava. Pri svim je istraživanim uvjetima nastao kalcit. Utvrđeno je da se specifična površina i prosječni promjer čestica kalcita, pripravljenog šaržnim postupkom, smanjuju s povećanjem temperature, dok se s povišenjem početne masene koncentracije poboljšava stupanj agregiranosti taloga. TKK pripravljen semikontinuiranim postupkom, vođenim pri niskim temperaturama ili visokim prezasićenostima, velike je specifične površine. Odabirom procesnih parametara semikontinuiranog postupka moguće je pripraviti kalcit u obliku romboedarskih, skalenoedarskih ili kuglastih čestica nanometarskih dimenzija

Molecular detection and genetic characterization of mumps virus

Virus mumpsa uzročnik je zaušnjaka, bolesti koja se može prevenirati cijepljenjem. Mumps je RNK virus koji se u kliničkim uzorcima i u supernatantima inficiranih staničnih kultura nakon izolacije RNK može detektirati RT-PCR testom. Prednosti RT-PCR testa su brzina, specifičnost i mogućnost detekcije malog broja kopija virusa. Genskom karakterizacijom i genotipizacijom virusa omogućeno je epidemiološko praćenje distribucije i cirkuliranja divljih tipova virusa mumpsa koji uzrokuju epidemije i u procijepljenim populacijama. Molekularna detekcija i genska karakterizacija divljih i cjepnih virusa mumpsa provodi se u Republici Hrvatskoj od kraja 90-tih godina.Mumps is an RNA virus that is a cause of the vaccine preventable disease, mumps. In clinical specimens and supernatants of the infected cell cultures its RNA is detectable by RT-PCR test. Advantages of RT-PCR are rapidity, specificity and sensitivity. Genetic characterization and genotyping are basis for molecular epidemiological surveillance of the wild type mumps virus. Mumps outbreaks are also detected in a highly vaccinated population. Molecular detection and characterization of wild and vaccine types of mumps virus has been performed in Croatia since the late nineties

Cas3 is a limiting factor for CRISPR-Cas immunity in Escherichia coli cells lacking H-NS

Background: CRISPR-Cas systems provide adaptive immunity to mobile genetic elements in prokaryotes. In many bacteria, including E. coli, a specialized ribonucleoprotein complex called Cascade enacts immunity by “an interference reaction" between CRISPR encoded RNA (crRNA) and invader DNA sequences called “protospacers”. Cascade recognizes invader DNA via short “protospacer adjacent motif” (PAM) sequences and crRNA-DNA complementarity. This triggers degradation of invader DNA by Cas3 protein and in some circumstances stimulates capture of new invader DNA protospacers for incorporation into CRISPR as “spacers” by Cas1 and Cas2 proteins, thus enhancing immunity. Co-expression of Cascade, Cas3 and crRNA is effective at giving E. coli cells resistance to phage lysis, if a transcriptional repressor of Cascade and CRISPR, H-NS, is inactivated (Δhns). We present further genetic analyses of the regulation of CRISPR-Cas mediated phage resistance in Δhns E. coli cells. Results: We observed that E. coli Type I-E CRISPR-Cas mediated resistance to phage λ was strongly temperature dependent, when repeating previously published experimental procedures. Further genetic analyses highlighted the importance of culture conditions for controlling the extent of CRISPR immunity in E. coli. These data identified that expression levels of cas3 is an important limiting factor for successful resistance to phage. Significantly, we describe the new identification that cas3 is also under transcriptional control by H-NS but that this is exerted only in stationary phase cells. Conclusions: Regulation of cas3 is responsive to phase of growth, and to growth temperature in E. coli, impacting on the efficacy of CRISPR-Cas immunity in these experimental systems