Thunen Institute of Agricultural Technology

Braunschweig, Germany

Thunen Institute of Agricultural Technology

Braunschweig, Germany
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Krull S.,Thunen Institute of Agricultural Technology | Hevekerl A.,Thunen Institute of Agricultural Technology | Kuenz A.,Thunen Institute of Agricultural Technology | Prusse U.,Thunen Institute of Agricultural Technology
Applied Microbiology and Biotechnology | Year: 2017

Itaconic acid is a promising organic acid and is commercially produced by submerged fermentation of Aspergillus terreus. The cultivation process of the sensitive filamentous fungus has been studied intensively since 1932, with respect to fermentation media components, oxygen supply, shearing rate, pH value, or culture method. Whereas increased final titers were achieved over the years, the productivity has so far remained quite low. In this study, the impact of the pH on the itaconic acid production was investigated in detail. The pH during the growth and production phase had a significant influence on the final itaconic acid concentration and pellet diameter. The highest itaconic acid concentration of 160 g/L was achieved at a 1.5-L scale within 6.7 days by raising and controlling the pH value to pH 3.4 in the production phase. An ammonia solution and an increased phosphate concentration were used with an itaconic acid yield of 0.46 (w/w) and an overall productivity of 0.99 g/L/h in a fed-batch mode. A cultivation with a lower phosphate concentration resulted in an equal final concentration with an increased yield of 0.58 (w/w) after 11.8 days and an overall productivity of 0.57 g/L/h. This optimized process was successfully transferred from a 1.5-L scale to a 15-L scale. After 9.7 days, comparable pellet morphology and a final concentration of 150 g/L itaconic acid was reached. This paper provides a process strategy to yield a final titer of itaconic acid from a wild-type strain of A. terreus which is in the same range as the well-known citric acid production. © 2017 Springer-Verlag Berlin Heidelberg


Hahne J.,Thunen Institute of Agricultural Technology | Pfeifer T.,DLG Testzentrum Technik und Betriebsmittel
Landtechnik | Year: 2017

Currently used bio filters are suited for odor reduction in livestock keeping but not for ammonia separation. Therefore it was the objective to develop a novel bio filter system which was able to ensure a high and long-lasting ammonia separation. This novel bio filter, which is equipped with a pH control in a water swamp beneath the filter layer and a conductivity control for water discharge, was investigated in terms of ammonia separation and nitrogen disposition over several months under practical conditions. The results show a stable ammonia separation of more than 88 % if certain consecutively described operating conditions are kept.


Stichnothe H.,Thunen Institute of Agricultural Technology | Schuchardt F.,Thunen Institute of Agricultural Technology | Rahutomo S.,Indonesian Oil Palm Research Institute
International Journal of Life Cycle Assessment | Year: 2014

Purpose: The aim of this paper is to evaluate assumptions and data used in calculations related to palm oil produced for biodiesel production relative to the European Renewable Energy Directive (EU-RED). The intent of this paper is not to review all assumptions and data, but rather to evaluate whether the methodology is applied in a consistent way and whether current default values address relevant management practices of palm oil production systems. Methods: The GHG calculation method provided in Annex V of the EU-RED was used to calculate the GHG-emissions from palm oil production systems. Moreover, the internal nitrogen recycling on the plantation was calculated based on monitoring data in North Sumatra. Results and discussion: A calculation methodology is detailed in Annex V of the EU-RED. Some important aspects necessary to calculate the GHG emission savings correctly are insufficiently considered, e.g.: • "Nitrogen recycling" within the plantation due to fronds remaining on the plantation is ignored. The associated organic N-input to the plantation and the resulting nitrous oxide emissions is not considered within the calculations, despite crop residues being taken into account for annual crops in the BIOGRACE tool. • The calculation of GHG-emissions from residue and waste water treatment is inappropriately implemented despite being a hot-spot for GHG emissions within the life cycle of palm oil and palm oil biodiesel. Additionally, no distinction is made between palm oil and palm kernel oil even though palm kernel oil is rarely used for biodiesel production. • The allocation procedure does not address the most relevant oil mill management practices. Palm oil mills produce crude palm oil (CPO) in addition either nuts or palm kernels and nut shells. In the first case, the nuts would be treated as co-products and upstream emissions would be allocated based on the energy content; in the second case the kernels would be treated as co-products while the shelöls are considered as waste without upstream emissions. This has a significant impact on the resulst or GHG savings, respectively. • It is not specified whether indirect GHG emissions from nitrogen oxide emission from the heat and power unit of palm oil mills should be taken into account. Conclusions and recommendations: In conclusion, the existing calculation methodology described in Annex V of the EU-RED and default values are insufficient for calculating the real GHG emission savings from palm oil and palm oil biodiesel. The current default values do not reflect relevant management practices. Additionally, they protect poor management practices, such as the disposal of empty fruit bunches (EFB), and lead to an overestimation of GHG savings from palm oil biodiesel. A default value for EFB disposal must be introduced because resulting GHG emissions are substantial. Organic nitrogen from fronds must be taken into account when calculating real GHG savings from palm oil biodiesel. Further, more conservative data for FFB yield and fugitive emissions from wastewater treatment should be introduced in order to foster environmental friendly management options. Moreover, credits for bioenergy production from crop residues should be allowed in order to foster the mobilization of currently unused biomass. © 2014 Springer-Verlag.


Clauss M.,Thunen Institute of Agricultural Technology
Landbauforschung Volkenrode | Year: 2015

To obtain insight into the particle size distributions of airborne micro-organisms in different environments, a literature search was conducted. More than 190 publications containing relevant data including sampling systems, sampling sites, measuring parameters, sample size and concentrations were included. The size distribution of airborne particles carrying micro-organisms is a well-investigated subject in the range of aerodynamic diameters (AD) of 0.65 urn to 12 urn for many micro-organism groups and environments. It depends primarily on the sampling location and the type of source as well as the method of aerosolisation. Highest median shares of large bacteria-laden particles were found in livestock husbandry and in waste management. Sampling height above ground, air humidity, temperature and solar radiation may also influence particle size. For moulds, the median size distributions in air largely represent the size ranges of their spores. There is little knowledge about particles > 12 urn AD and the actual number of micro-organisms in different particle size classes. Few studies suggest that most micro-organisms are in particle size fractions > 10 urn AD. Future investigations should use sampling systems with high inlet efficiencies for particles > 20 urn AD, and allow sampling in a liquid to separate micro-organisms from aggregates. These systems should rather sample the health and environmentally relevant particle size fractions PM 2.5, PM 4, PM 10 and the total dust to allow for a more precise derivation of health and environmental effects.


Hevekerl A.,Thunen Institute of Agricultural Technology | Kuenz A.,Thunen Institute of Agricultural Technology | Vorlop K.-D.,Thunen Institute of Agricultural Technology
Applied Microbiology and Biotechnology | Year: 2014

Itaconic acid is an important industrial building block and is produced by the filamentous fungi Aspergillus terreus. To make the optimization process more efficient, a scale-down from shake flasks to microtiter plates was performed. This resulted in comparable product formations, and 87.7 g/L itaconic acid was formed after 10 days of cultivation in the microtiter plate. The components of the minimal medium were varied independently for a media optimization. This resulted in an increase of the itaconic acid concentration by a variation of the KH2PO4 and CuSO4 concentrations. The cultivation with a higher KH2PO4 concentration in a 400-mL bioreactor showed an increase in the maximum productivity of 1.88 g/L/h, which was an increase of 74 % in comparison to the reference. Neither the phosphate concentration nor the nitrogen sources were limited at the start of the product formation. This showed that a limitation of these substances is not necessary for the itaconic acid formation. © 2014 Springer-Verlag.


Hevekerl A.,Thunen Institute of Agricultural Technology | Kuenz A.,Thunen Institute of Agricultural Technology | Vorlop K.-D.,Thunen Institute of Agricultural Technology
Applied Microbiology and Biotechnology | Year: 2014

Itaconic acid is mainly produced with the filamentous fungi Aspergillus terreus. An increase in the pH during the production phase of the cultivation resulted in an increase in the itaconic acid concentration. The pH was raised by a single pH shift ranging from pH 4 to 6 or by a pH control to pH 3. Different lyes can be used for the pH shift, but ammonia solution has proven to be the best, because here the productivity does not drop after the pH shift. The highest itaconic acid concentration of 146 g/L was reached when a pH control to pH 3 was started after 2.1 days of cultivation. This is an increase of 68 % to the cultivation without pH control. When this technique was combined with previously found optimizations, a final itaconic acid concentration of 129 g/L was reached after 4.7 days of cultivation, resulting in a productivity of 1.15 g/L/h. © 2014, Springer-Verlag Berlin Heidelberg.


Hahne J.,Thunen Institute of Agricultural Technology
Landtechnik | Year: 2013

Relevant trace gas emissions from two chicken houses in small group housing were measured from 2009 to 2012. The emissions were varying widely and, in case of ammonia, depending on the dung removal rates. Between those the ammonia emission increased daily up to 120 %. The trace gas and particulate matter emissions as well could be correlated with the volume flow at a constant stable management. While methane, nitrous oxide and hydrogen sulfphide emissions were low with 9 ± 7, 7 ± 2 and 4 ± 1 g per head and year at specific air flow rates of 8.2 ± 1.4 m3 per head and hour, ammonia emission for this housing system was in a common range with 148 ± 29 g per head and year. The carbon dioxide emission exceeded with 46 kg per head and year the ammonia emission by a factor of 311. Specific odor emissions varied with 15-84 odor units (OU) per second (s) and livestock unit (LU). In mean the odor emission was 43 OU s-1 LU-1.


Kallbach M.,Thunen Institute of Agricultural Technology | Horn S.,Thunen Institute of Agricultural Technology | Kuenz A.,Thunen Institute of Agricultural Technology | Prusse U.,Thunen Institute of Agricultural Technology
Applied Microbiology and Biotechnology | Year: 2016

Biotechnologically produced 2,3-butanediol (2,3-BDO) is a potential starting material for industrial bulk chemicals such as butadiene or methyl ethyl ketone which are currently produced from fossil feedstocks. So far, the highest 2,3-BDO concentrations have been obtained with risk group 2 microorganisms. In this study, three risk group 1 microorganisms are presented that are so far unknown for an efficient production of 2,3-BDO. The strains Bacillus atrophaeus NRS-213, Bacillus mojavensis B-14698, and Bacillus vallismortis B-14891 were evaluated regarding their ability to produce high 2,3-BDO concentrations with a broad range of different carbon sources. A maximum 2,3-BDO concentration of 60.4 g/L was reached with the strain B. vallismortis B-14891 with an initial glucose concentration of 200 g/L within 55 h in a batch cultivation. Besides glucose, B. vallismortis B-14891 converts 14 different substrates that can be obtained from residual biomass sources to 2,3-BDO. Therefore B. vallismortis B-14891 is a promising candidate for the large-scale production of 2,3-BDO with low-cost substrates. © 2016 Springer-Verlag Berlin Heidelberg


Willke T.,Thunen Institute of Agricultural Technology
Applied Microbiology and Biotechnology | Year: 2014

This paper presents an updated critical review about several attempts to contribute methionine (Met) to the world market with an emphasis on fermentation processes, especially from natural biological sources. Analytical methods for the determination of methionine are reviewed as well as applications in feed, food, pharmacy, and medicine. Fermentation studies published within the last five decades are elucidated critically, mainly with respect to the sulfur balance, substrate yield, and the analytical validity. From all the published fermentation data, it can be concluded that up to now no more than 5 g/L methionine are achievable without using genetically modified organisms (GMOs). The highest l-methionine concentration from natural sources reached so far amounts to 35 g/L and is published as a patent using a GMO of Escherichia coli. The review closes with a comprehensive overview of the role and activities of global methionine manufacturers. Some current market data is also presented. © 2014, Springer-Verlag Berlin Heidelberg.


Klotz S.,Thunen Institute of Agricultural Technology | Kaufmann N.,Thunen Institute of Agricultural Technology | Kuenz A.,Thunen Institute of Agricultural Technology | Prusse U.,Thunen Institute of Agricultural Technology
Applied Microbiology and Biotechnology | Year: 2016

The fermentation process of l-lactic acid is well known. Little importance was attached to d-lactic acid, but in the past 10 years, d-lactic acid gained significantly in importance. d-Lactic acid is an interesting precursor for manufacturing heat-resistant polylactic acid (PLA) bioplastics which can be widely used, for example as packaging material, coatings, for textiles or in the automotive industry. This review provides a comprehensive overview of the most recent developments, including a spectrum of studied microorganisms and their capabilities for the production of d-lactic acid. Additionally, the technological achievements in biotechnological d-lactic acid production including fermentation techniques like fed batch, simultaneous saccharification, and fermentation and continuous techniques are presented. Attention is also turned to suitable alternative substrates and their applicability in fermentation processes. Furthermore, advantages and disadvantages of product recovery and purification are discussed. Economic aspects of PLA are pointed out, and the present industrial producers of lactic acid are briefly introduced. © 2016 Springer-Verlag Berlin Heidelberg

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