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.
2019
Authors
Andre van Eerde Aniko Varnai John-Kristian Jameson Lisa Paruch Anders Moen Jan Haug Anonsen Piotr Chylenski Hege Særvold Steen Inger Heldal Ralph Bock Vincent Eijsink Jihong Liu ClarkeAbstract
Sustainable production of biofuels from lignocellulose feedstocks depends on cheap enzymes for degradation of such biomass. Plants offer a safe and cost‐effective production platform for biopharmaceuticals, vaccines and industrial enzymes boosting biomass conversion to biofuels. Production of intact and functional protein is a prerequisite for large‐scale protein production, and extensive host‐specific post‐translational modifications (PTMs) often affect the catalytic properties and stability of recombinant enzymes. Here we investigated the impact of plant PTMs on enzyme performance and stability of the major cellobiohydrolase TrCel7A from Trichoderma reesei, an industrially relevant enzyme. TrCel7A was produced in Nicotiana benthamiana using a vacuum‐based transient expression technology, and this recombinant enzyme (TrCel7Arec) was compared with the native fungal enzyme (TrCel7Anat) in terms of PTMs and catalytic activity on commercial and industrial substrates. We show that the N‐terminal glutamate of TrCel7Arec was correctly processed by N. benthamiana to a pyroglutamate, critical for protein structure, while the linker region of TrCel7Arec was vulnerable to proteolytic digestion during protein production due to the absence of O‐mannosylation in the plant host as compared with the native protein. In general, the purified full‐length TrCel7Arec had 25% lower catalytic activity than TrCel7Anat and impaired substrate‐binding properties, which can be attributed to larger N‐glycans and lack of O‐glycans in TrCel7Arec. All in all, our study reveals that the glycosylation machinery of N. benthamiana needs tailoring to optimize the production of efficient cellulases.
Authors
Zhichao Chen Yuxin Miao Junjun Lu Lan Zhou Yue Li Hongyan Zhang Weidong Lou Zheng Zhang Krzysztof Kusnierek Changhua LiuAbstract
Improving nitrogen (N) management of small-scale farming systems in developing countries is crucially important for food security and sustainable development of world agriculture, but it is also very challenging. The N Nutrition Index (NNI) is a reliable indicator for crop N status, and there is an urgent need to develop an effective method to non-destructively estimate crop NNI in different smallholder farmer fields to guide in-season N management. The eBee fixed-wing unmanned aerial vehicle (UAV)-based remote sensing system, a ready-to-deploy aircraft with a Parrot Sequoia+ multispectral camera onboard, has been used for applications in precision agriculture. The objectives of this study were to (i) determine the potential of using fixed-wing UAV-based multispectral remote sensing for non-destructive estimation of winter wheat NNI in different smallholder farmer fields across the study village in the North China Plain (NCP) and (ii) develop a practical strategy for village-scale winter wheat N status diagnosis in small scale farming systems. Four plot experiments were conducted within farmer fields in 2016 and 2017 in a village of Laoling County, Shandong Province in the NCP for evaluation of a published critical N dilution curve and for serving as reference plots. UAV remote sensing images were collected from all the fields across the village in 2017 and 2018. About 150 plant samples were collected from farmer fields and plot experiments each year for ground truthing. Two indirect and two direct approaches were evaluated for estimating NNI using vegetation indices (VIs). To facilitate practical applications, the performance of three commonly used normalized difference VIs were compared with the top performing VIs selected from 59 tested indices. The most practical and stable method was using VIs to calculate N sufficiency index (NSI) and then to estimate NNI non-destructively (R2 = 0.53–0.56). Using NSI thresholds to diagnose N status directly was quite stable, with a 57–59% diagnostic accuracy rate. This strategy is practical and least affected by the choice of VIs across fields, varieties, and years. This study demonstrates that fixed-wing UAV–based remote sensing is a promising technology for in-season diagnosis of winter wheat N status in smallholder farmer fields at village scale. The considerable variability in local soil conditions and crop management practices influenced the overall accuracy of N diagnosis, so more studies are needed to further validate and optimize the reported strategy and consecutively develop practical UAV remote sensing–based in-season N recommendation methods.
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Authors
Liv Jorunn HindAbstract
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Authors
Marleen Pallandt Bernhard Ahrens Markus Reichstein Holger Lange Marion Schrumpf Sönke ZaehleAbstract
The role of soil moisture on organic matter decomposition remains poorly understood and underrepresented in coupled global climate models. Traditionally, organic matter decomposition is represented as simple first- or second order kinetics in such models, using mostly empirical functions for temperature and moisture controls, and without considering microbial interactions. We use the Dual Michaelis-Menten (DAMM) model (Davidson et al. 2012) to simulate simultaneous temperature and moisture controls on decomposition rates. Microbial controls on decomposition in relation to changes in soil moisture and temperature are implicitly simulated with DAMM: Soil moisture affects the available substrate (SOC) and oxygen available for decomposition and reduces the maximal, temperature driven decomposition rate (Vmax). We apply the DAMM model on vertically resolved data from the most recent coupled model intercomparison project (CMIP5) and gridded global SOC values (SoilGrids). We study the potential decomposition rates for a historic period (1976 - 2006) and a period under the RCP8.5 climate change scenario (2070-2099) for 5 soil layers up to 1m depth. Our key finding is that the inclusion of soil moisture controls has diverging effects on both the speed and direction of projected decomposition rates, compared to a temperature-only approach. The majority of these changes are driven by soil moisture through substrate limitation, rather than oxygen diffusion limitation. In deeper soil layers, oxygen diffusion limitation plays a stronger role. Our study highlights the need for inclusion of soil moisture interactions in coupled global climate models. Our findings could be particularly important for boreal soils, which store a major fraction of Earth’s SOC stocks and where temperature increases and soil moisture changes are expected to be largest.
Abstract
Minimising outputs of waste and pollution by recycling and efficient utilisation of renewable resources is of common interest for organic agriculture and the concepts of circular and bioeconomy. However, in practice, many efforts to increase recycling of various biological materials in organic agriculture are hampered because standards for certified organic production and processing tend to prefer natural products while avoiding processing and especially chemical processes. This creates several dilemmas and weakens the position of organic agriculture as a spear head in the development of a better resource utilisation which will reduce environmental impacts from food production. Based on practical examples derived from projects aimed at better utilisation of residual materials in various food chains, this paper presents some of these dilemmas. Our aim is to initiate a discussion among organic agriculture stakeholders about the regulations for organic production, how they restrict recycling and a better utilisation of valuable resources, and how this can be overcome.
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In studies of consumption of local food specialties individuals' personality are rarely included. In this article we want to expand and give nuances to the understanding of what characterizes these consumers and ask: Are there any common personality traits, or personal characteristics of these consumers? We make use of the Big Five personality model to unpack the relation between individual's personality and choices of local food specialties. This model consists of the following five personal traits: Extraversion, Agreeableness, Conscientiousness, Neuroticism, Openness to Experience. These personality traits are hidden but through questions regarding behavior the traits may be retrieved. In order to construct latent variables to represent measures of these traits, we apply Item Response Theory (IRT). Socioeconomic variables are combined with personality traits in logistic regression models to find the connection between personality and choice of Norwegian local food specialties. The results show that in all models the latent variable Openness to Experience is a significant predictor for choice of local food specialties. This personality trait was one of the most important predictors in all the choices made by the individuals. Openness to Experience is characterized by fantasy, aesthetic sensitivity, attentiveness to inner feelings, preference for variety, and intellectual curiosity.
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No abstract has been registered