Til dokument

Sammendrag

Both enzymatic or oxidative carotenoids cleavages can often occur in nature and produce a wide range of bioactive apocarotenoids. Considering that no detailed information is available in the literature regarding the occurrence of apocarotenoids in microalgae species, the aim of this study was to study the extraction and characterization of apocarotenoids in four different microalgae strains: Chlamydomonas sp. CCMP 2294, Tetraselmis chuii SAG 8-6, Nannochloropsis gaditana CCMP 526, and Chlorella sorokiniana NIVA-CHL 176. This was done for the first time using an online method coupling supercritical fluid extraction and supercritical fluid chromatography tandem mass spectrometry. A total of 29 different apocarotenoids, including various apocarotenoid fatty acid esters, were detected: apo-12’-zeaxanthinal, β-apo-12’-carotenal, apo-12-luteinal, and apo-12’-violaxanthal. These were detected in all the investigated strains together with the two apocarotenoid esters, apo-10’-zeaxanthinal-C4:0 and apo-8’-zeaxanthinal-C8:0. The overall extraction and detection time for the apocarotenoids was less than 10 min, including apocarotenoids esters, with an overall analysis time of less than 20 min. Moreover, preliminary quantitative data showed that the β-apo-8’-carotenal content was around 0.8% and 2.4% of the parent carotenoid, in the C. sorokiniana and T. chuii strains, respectively. This methodology could be applied as a selective and efficient method for the apocarotenoids detection.

Sammendrag

With regard to the rapidly growing world population, microalgae can be regarded as one of the most promising resources for the sustainable supply of commodities for food and feed applications. Although the use of commercial microalgae for food has been mainly limited to dietary supplements, the recent development of more cost-effective production technology makes it feasible to explore various other food applications. In the project ALGAE TO FUTURE, funded by the Norwegian Research Council, we have developed a consortium of 20 research and industry partners to approach this topic from multiple angles merging multiple research fields. The Vision is to contribute towards a viable Norwegian microalgae industry within 10 years. The focus of the research is on bioprocess developments linked to lipids, carbohydrates and proteins, where cultivation conditions are used to obtain microalgae biomass with specific nutrient composition targeting specific products, without use of GMO. We have chosen to target the development of 3 example products, namely bread, beer and aquaculture feed, that will be produced in a commercial context towards the end of the project. These case studies have been chosen in order to demonstrate the use of algal biomass from various algae species with highly different nutrient composition suitable for different products. The project combines expertise on algae cultivation and optimisation at lab and pilot scales, fish feeding technology, biorefining, bioeconomy, baking technology, broadcast journalism and animation, food quality and safety with the experience of innovative farmer entrepreneurs, professional bakers, brewers and fish-feed producers in a cross-disciplinary manner.

Sammendrag

Several species of microalgae and phototrophic bacteria are able to produce hydrogen under certain conditions. A range of different photobioreactor systems have been used by different research groups for lab-scale hydrogen production experiments, and some few attempts have been made to upscale the hydrogen production process. Even though a photobioreactor system for hydrogen production does require special construction properties (e.g., hydrogen tight, mixing by other means than bubbling with air), only very few attempts have been made to design photobioreactors specifically for the purpose of hydrogen production. We have constructed a flat panel photobioreactor system that can be used in two modes: either for the cultivation of phototrophic microorganisms (upright and bubbling) or for the production of hydrogen or other anaerobic products (mixing by “rocking motion”). Special emphasis has been taken to avoid any hydrogen leakages, both by means of constructional and material choices. The flat plate photobioreactor system is controlled by a custom-built control system that can log and control temperature, pH, and optical density and additionally log the amount of produced gas and dissolved oxygen concentration. This paper summarizes the status in the field of photobioreactors for hydrogen production and describes in detail the design and construction of a purpose-built flat panel photobioreactor system, optimized for hydrogen production in terms of structural functionality, durability, performance, and selection of materials. The motivations for the choices made during the design process and advantages/disadvantages of previous designs are discussed.

Sammendrag

Behovet for vegetabilsk protein til dyrefôr i norsk landbruk, blir per i dag ikke dekket av norskprodusert protein, og norsk kjøtt og melkeproduksjon er i dag avhengig av import. Totalt er 44% av ingrediensene til norsk kraftfôr importert, og import utgjør 93% av proteininnholdet. Mikroalger har høyere proteininnhold enn både tradisjonelle og alternative vegetabilske proteinkilder, og har i tillegg høyt innhold av andre næringsstoff som vitaminer, mineraler, flerumettede fettsyrer og antioksidanter. Næringsinnhold vil variere mye mellom artene, og i mange tilfeller kan næringssammensetningen styres med bruk av dyrkingsbetingelser. Forsøk med mikroalger som fôrkilde til storfe, gris og andre husdyr, har gitt gode resultater mht fôraksept, fôropptak, fordøyelighet, veksthastighet, totalvekt, fertilitet, melkeproduksjon, og proteininnhold i melk. Mikroalger blir i dag produsert kommersielt mange ulike steder i verden, og det meste blir solgt som dyrefôr eller helsekost. Det har vært mye forskning innen reaktorteknologi for produksjon av mikroalger de siste tiårene, og mange varianter av fotobioreaktorer har vært utprøvd. Algedyrking på norske gårdsbruk krever at dyrkingsteknologien blir tilpasset ressursgrunnlaget som foreligger, for optimal produksjon og bærekraft mht økonomi, miljø og ressursbruk. Informasjon som...

Sammendrag

The production of hydrogen in green algae is catalyzed by FeFe- hydrogenases, which have high conversion efficiency and high oxygen sensitivity. Most green algae analyzed to date where hydrogenase genes are detected, have been shown to contain two distinct hydrogenases. However, very little is known about which functions the two different enzymes represent. There are also many unknowns within the mechanisms behind hydrogen production as to the roles hydrogenases play under different conditions, and consequently also about the potential for optimization of a hydrogen production process which could be found in this respect. The presented study focuses on the possibility for presence of more than two hydrogenases in a single green alga. A large number of degenerate primers were designed and used to produce 3"-RACE products, which in turn were used to design gene specific primers used for PCR and 5"-RACE reactions. The sequences were aligned with known algal hydrogenases to identify products which had homology to these. Products where homology was identified were then explored further. A high number of clones from each band were sequenced to identify products with similar lengths which would not show up as separate bands on a gel. Sequences found to have homology with algal hydrogenases were translated into putative amino acid sequences and analyzed further to obtain detailed information about the presence of specific amino acids with known functions in the enzyme. This information was used to evaluate the likelihood of these transcripts coding for true hydrogenases, versus hydrogenase-like or narf-like proteins. Conclusion: Evidence showing that Chlamydomonas noctigama is able to transcribe three genes which share a significant number of characteristics with other known algal FeFe-hydrogenases is presented . The three genes have been annotated hydA1, hydA2 and hydA3.

Sammendrag

Green algae are known to produce H2 under sulphur deprivation in a process called bio­photolysis, where solar energy is used to split water and generate O2 and H2. There is still considerable potential for im­provement and very little is known about how this mechanism varies between species. This is part of Bioforsk research activities linked to green algae and H2 production. In order to make a H2 production process from algae economically viable, we face several challenges, including bioreactor design, optimisation of environ­mental conditions, efficiency improvement by genetic and metabolic engineering. One possibility for improving the economical potential of a hydrogen production process also includes exploitation of the algal biomass which, as a result of stress reactions, may pro­duce metabolites with pharmaceutical value.  Joining forces with The Norwegian University of Life Science (UMB) and The Norwegian Forest and Landscape Institute, Bioforsk has established The Norwegian Centre for Bioenergy Research. Bioforsk has also taken a leading role on biogas in the newly established CenBio - a national Centre for Environmental- friendly Energy Research. The modern biogas laboratories are located close to facilities for plant growth studies, making them easy accessible for experimental studies of the entire chain from biomass to fertiliser. Research activities include innovative pre-treatment of substrates for increased biogas yield, effects of substrate mixtures for biogas production and digestate quality, biogas potential and biogas process studies, digestates as fertiliser, and effects on the environment and climate

Sammendrag

Green microalgae can be used for a number of commercial applications, including health food for human consumption, aquaculture and animal feed, coloring agents, cosmetics and pharmaceuticals. Several products from green algae that are in use today, consist of metabolites which can be extracted from the algal biomass. The most well known examples are the carotenoids astaxanthin and Β-carotene, which are used as coloring agents and for health promoting purposes. Many species of green algae are able to produce valuable components for different uses, examples are antioxidants, several different carotenoids, polyunsaturated fatty acids, vitamins, anticancer and antiviral drugs. In many cases these components are secondary metabolites which are produced when the algae are exposed for stress conditions like for example nutrient deprivation, light intensity, temperature, salinity, pH and other. In other cases the components have been detected in algae grown under optimal conditions, and little is known about how an optimal production of each product could be induced and how their production would react to stress conditions.  Some green algae have shown the ability to produce significant amounts of hydrogen gas during sulfur deprivation, a process which is currently extensively studied. At the moment, the majority of research in this field has focused on the model organism Chlamydomonas reinhardtii, but other species of green algae have also showed this ability. Currently there is scarce information available regarding the possibility for producing hydrogen and other valuable components in the same process. This study explores stress conditions which are known to induce production of the different valuable products in comparison with stress reactions leading to hydrogen production. Wild type species of green microalgae with ability to produce hydrogen during anaerobic conditions, and during sulfur deprivation are compared to species with known ability to produce high amounts of certain valuable metabolites. . This information is explored in order to form a basis for selection of wild type species for a future multidiciplinary process, where hydrogen production from solar energy is combined with production of valuable metabolites and other commercial uses of the algal biomass.

Til dokument

Sammendrag

Hydrogen production through biological routes is promising because they are environmentally friendly. Hydrogen production through biophotolysis or photofermentation is usually a two stage process. In the first stage CO2 is utilized for biomass production which is followed by hydrogen production in the second stage in anaerobic/sulfur deprived conditions in the next stage. The major challenges confronting the large scale production of biomass/hydrogen are limited not only on the performance of the photo bioreactors in which light penetration in dense cultures is a major bottleneck but also on the microbiology, biochemistry and molecular biology of the organisms. Other dependable factors include area/ volume (A/V) ratio, mode of agitation, temperature and gas exchange. Photobioreactors of different geometries are reported for biohydrogen production-Tubular, Flat plate, Fermentor type etc. Every reactor has its own advantages and disadvantages. No reactor is ideal for this purpose. Airlift, helical tubular and flat plate reactors are found most suitable with respect to biomass production. These bioreactors may be employed for hydrogen production with necessary modifications to overcome the existing bottlenecks like gas hold up, oxygen toxicity and improved agitation system. This review article attempts to focus on existing photobioreactors with respect to biomass generation and hydrogen production and the steps taken to improve its performance through engineering innovation that definitely help in the future construction of photobioreactors.

Sammendrag

Twenty-one species of green algae isolated from marine, freshwater and terrestrial environments were screened for the ability to produce H2 under anaerobic conditions. Seven strains found positive for H2 production under anaerobic conditions were also screened for the ability to produce H2 under sulfur (S) deprivation. In addition to the traditional model species Chlamydomonas reinhardtii, C. noctigama (freshwater) and C. euryale (brackish water) were able to produce significant amounts of H2 under S-deprivation. These species were also able to utilize acetate as a substrate for growth in light. The S-deprivation experiments were performed under photoheterotrophic conditions in a purpose-specific designed bioreactor, and it was shown that an automated pH adjustment feature was essential to maintain a stable pH in the cultures. Several materials commonly used in bioreactors, such as rubber materials, plastics and steel alloys, had a negative effect on the survival of S-deprived algae cultures. Unexpectedly, traces of H2 were produced under S-deprivation during O2 saturation in the cultures, possibly derived from local anaerobic environments formed in algal biofilms on the membranes covering the O2 electrodes.

Sammendrag

Many areas of algae technology have developed over the last decades, and there is an established market for products derived from algae, dominated by health food and aquaculture. In addition, the interest for active biomolecules from algae is increasing rapidly. The need for CO2 management, in particular capture and storage is currently an important technological, economical and global political issue and will continue to be so until alternative energy sources and energy carriers diminish the need for fossil fuels. This review summarizes in an integrated manner different technologies for use of algae, demonstrating the possibility of combining different areas of algae technology to capture CO2 and using the obtained algal biomass for various industrial applications thus bringing added value to the capturing and storage processes. Furthermore, we emphasize the use of algae in a novel biological process which produces H2 directly from solar energy in contrast to the conventional CO2 neutral biological methods. This biological process is a part of the proposed integrated CO2 management scheme.

Sammendrag

Many different species of microorganisms have one or more hydrogenase enzymes that reduce protons to molecular hydrogen under certain conditions. Upon sulfur deprivation, green algae can produce relatively large amounts of hydrogen in a sustainable process. The majority of research in this field has focused on Chlamydomonas reinhardtii, but other species of green algae are also able to produce hydrogen under sulfur deprivation. Using PCR reactions, we examined the presence of hydrogenase genes in marine and fresh water species of green algae that were able to produce hydrogen under sulfur deprived conditions. Primers were designed from conserved regions of the sequence of the two hydrogenase genes in C. reinhardtii, and used to screen for the presence of similar gene sequences in other species. PCR products that were sequenced suggest that genes for hydrogenase are present in C. noctigama and other species. Similarities and differences in the sequences of hydrogenase genes between C. reinhardtii and other species, will be presented.

Sammendrag

The sun is an abundant energy source, and increasing efforts are made to find more efficient ways to exploit it, than commonly used today. Hydrogen is considered to be the energy carrier of the future, and the potential for a sustainable system where hydrogen is obtained directly from solar energy, has been studied extensively. One alternative is the process of biophotolysis. Sulfur starvation of the green algae Chlamydomonas reinhardtii is known to cause hydrogen production under illumination, by biophotolysis where solar energy is used to produce significant amounts of hydrogen involving parts of the photosynthetic process. So far, little is known about this process in other species, and in this work we have investigated different species of green algae with respect to hydrogen production under sulfur starvation. A number of algae cultures were screened with respect to physiological response to sulfur deprivation in small-scale laboratory cultures under controlled conditions. Test parameters included hydrogen production, reduction of oxygen production, changes in morphology and other aspects of physiology. Investigations of oxygen sensitivity of hydrogenases were also performed. It was shown that other species than C. reinhardtii are able to produce hydrogen under sulfur deprivation.

Sammendrag

Most energy carriers that are in common use today originate from solar energy. Hydrogen is considered to be the energy carrier of the future, and the potential for a sustainable system where hydrogen is obtained directly from solar energy, has been studied by several researchers over the years. Several groups of microorganisms have shown the ability to produce hydrogen by natural biological processes using solar energy. Efforts have been made to understand the mechanisms involved in photobiological hydrogen production from these organisms, and to optimise the process. This work has recently resulted in a significant breakthrough. It  has been discovered that some species of green algae have the ability to produce significant amounts of hydrogen during sulphur starvation, which allows hydrogen to be produced in light. However, very little is known about how this process varies between species. We have chosen to investigate green algae, with the intention to examine a variety of species for hydrogen production during sulphur starvation. A number of algae cultures were screened with respect to physiological response to sulphur deprivation in small-scale laboratory cultures under controlled conditions. Results from both marine and fresh water algae will be presented.