Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Authors
Giorgia Carnovale Shaun Allan Leivers Filipa Rosa Hans Ragnar Norli Edvard Hortemo Trude Wicklund Svein Jarle Horn Kari SkjånesAbstract
Microalgal biomass is widely studied for its possible application in food and human nutrition due to its multiple potential health benefits, and to address raising sustainability concerns. An interesting field whereby to further explore the application of microalgae is that of beer brewing, due to the capacity of some species to accumulate large amounts of starch under specific growth conditions. The marine species Tetraselmis chui is a well-known starch producer, and was selected in this study for the production of biomass to be explored as an active ingredient in beer brewing. Cultivation was performed under nitrogen deprivation in 250 L tubular photobioreactors, producing a biomass containing 50% starch. The properties of high-starch microalgal biomass in a traditional mashing process were then assessed to identify critical steps and challenges, test the efficiency of fermentable sugar release, and develop a protocol for small-scale brewing trials. Finally, T. chui was successfully integrated at a small scale into the brewing process as an active ingredient, producing microalgae-enriched beer containing up to 20% algal biomass. The addition of microalgae had a noticeable effect on the beer properties, resulting in a product with distinct sensory properties. Regulation of pH proved to be a key parameter in the process.
Authors
Andre van Eerde Aniko Varnai Yanliang Wang Lisa Paruch John-Kristian Jameson Fen Qiao Hans Geir Eiken Hang Su Vincent Eijsink Jihong Liu ClarkeAbstract
Giant panda could have bamboo as their exclusive diet for about 2 million years because of the contribution of numerous enzymes produced by their gut bacteria, for instance laccases. Laccases are blue multi-copper oxidases that catalyze the oxidation of a broad spectrum of phenolic and aromatic compounds with water as the only byproduct. As a “green enzyme,” laccases have potential in industrial applications, for example, when dealing with degradation of recalcitrant biopolymers, such as lignin. In the current study, a bacterial laccase, Lac51, originating from Pseudomonas putida and identified in the gut microbiome of the giant panda’s gut was transiently expressed in the non-food plant Nicotiana benthamiana and characterized. Our results show that recombinant Lac51 exhibits bacterial laccase properties, with optimal pH and temperature at 7–8 and 40°C, respectively, when using syringaldazine as substrate. Moreover, we demonstrate the functional capability of the plant expressed Lac51 to oxidize lignin using selected lignin monomers that serve as substrates of Lac51. In summary, our study demonstrates the potential of green and non-food plants as a viable enzyme production platform for bacterial laccases. This result enriches our understanding of plant-made enzymes, as, to our knowledge, Lac51 is the first functional recombinant laccase produced in plants.
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No abstract has been registered
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No abstract has been registered
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Soil disinfestation by steaming is being reconsidered for its efficiency in controlling or even eradicating pathogens, nematodes and weed seeds, particularly to avoid excess use of pesticides. Most weeds within a field result from seeds in the soil seedbank and therefore management of weed seeds in the soil seedbank offers practical long-term management of weeds, especially those difficult to control. We investigated the possibility of thermal control of seeds of grass weeds Bromus sterilis (barren brome) and Echinochloa crus-galli (barnyardgrass) using a prototype of a soil steaming device. Five different soil temperatures of 60, 70, 80, 90 and 99°C with an exposure duration of 3 min were tested. Four replications of 50 seeds of each species were placed in polypropylene-fleece bags. Bags in the same replicate of each target temperature were placed at the bottom of one plastic perforated basket container and covered by a 7-cm soil layer. Each basket was placed in the steaming container and steam was released from the top and vacuumed from the bottom of the container. Soil temperature was monitored by 10 thermocouples and steaming was stopped when 5 of the thermocouples had reached the target temperature. The basket was then removed from the steaming container after 3 min exposure time. Bags were taken out, opened, placed on soil surface in pots and covered by a thin layer of soil. Seed germination was followed for 8 weeks in the greenhouse. Non-steamed seeds were used as controls. It was shown that soil temperatures of 60, 70, 80, 90 and 99°C lasting for 3 min reduced the seed germination of barren brome by 83, 100, 100, 95 and 100% and seed germination of barnyardgrass by 74, 69, 83, 89 and 100% respectively, compared to the controls. Germination rate of control seeds were 94 and 71% for barren brome and barnyardgrass, respectively. These results show a promising seed mortality level of these two weed species by steaming and that steam is a potential method to control weed seeds, however further studies are needed to investigate the effect of other factors such as soil type and moisture content. Keywords: Non-chemical weed control, thermal soil disinfection, weed seedbank
Abstract
Invasive plant propagative material can be introduced to new regions as contaminants in soil. Therefore, moving soil should be done only when the soil has been verified to be free of invasive species. Stationary soil steaming as a non-chemical control method has the potential to disinfect soil masses contaminated with invasive species. We investigated the possibility of thermal control of propagative material of Bohemian knotweed (Reynoutria × bohemica) in two experiments using a prototype of a soil steaming device. Five soil temperatures of 60, 70, 80, 90 and 99 °C with an exposure duration of 3 min were tested. In each replicate and target temperature, rhizome cuttings containing at least two buds and shoot clumps were placed at the bottom of a plastic perforated basket and covered by a 7-cm soil layer. Each basket was placed in the steaming container and steam was released from the top and vacuumed from the bottom. Soil temperature was monitored by 10 thermocouples and steaming was stopped when 5 of the thermocouples had reached the target temperature. The basket was then removed from the steaming container after 3 min. Plant materials were taken out and planted in pots. Buds sprouting was followed for 8 weeks. Non-steamed plant materials were used as controls. Results showed 100% rhizome death at soil temperatures of ≥70 and 99 °C in the first and second experiments, respectively. Shoot clumps death was obtained at ≥90 °C in both experiments. These results showed that steaming at 99 °C for 3 min can guarantee control of Bohemian knotweed in infested soils supporting the steam treatment as a potential method of disinfecting soil against invasive species. However, depending on the intended re-use of the soil, further studies are needed on the effect of potential negative impacts of high temperatures on the soil quality.
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No abstract has been registered
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Weed-free zone underneath apple trees is important to maximize vegetative growth, fruit yield- and quality. Glyphosate applied twice is the usual strategy in apple orchards in Norway. Due to uncertain future of glyphosate there is a need for alternative strategies. A field trial was conducted during 2021 in an orchard (three-year-old trees). Five alternative strategies were tested: 1) Hot water at 3 L m-2 x 3 (spring, early summer, summer), 2) Hot water at 6 L m-2 x 3 (times as previous), 3) Pelargonic acid at full dose (10.9 kg a.s. ha-1) x 1 (early summer), 4) Pelargonic acid at half dose (5.44 kg a.s. ha-1) x 2 (spring, early summer), and 5) Rotary hoe x 3 (early spring, early summer, summer). Glyphosate at 1.08 kg a.s. ha-1 x 2 (early summer, summer) was included as reference strategy. Hot water (about 80 C, 0.1 bar) was applied with a commercial machine (Heatweed Technologies, Norway). Visual assessments of percentage of ground covered by living vegetation were used to estimate weed control efficacy. Dominating species were Taraxacum officinale, Tripleurospermum inodorum, Poa annua, Polygonum aviculare, Galium aparine, Viola arvensis and Senecio vulgaris. Assessed mid-summer (June 24), hot water applied twice (both 3 L m-2 and 6 L m-2) showed very high efficacies, both about 90%. Pelargonic acid showed rather low efficacies, about 15% (10.9 kg a.s. ha-1 x 1) and 45% (5.44 kg a.s. ha-1 x 2). Rotary hoe twice had almost 60%. Efficacy of glyphosate once was 75%. The last assessment was conducted in mid-July, i.e. about 1-2 weeks after the last application of hot water, rotary hoe and glyphosate. The two hot water strategies resulted in very good weed control, i.e.
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No abstract has been registered
Abstract
No abstract has been registered