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    Item type:Publication, Access status: with files ,
    From biomass to bioeconomy: engineering biocatalytic phosphorus mobilization from plant residues prior to animal feeding
    (2025)
    Widderich, Niklas Johannes Heinrich
    ;
    Liese, Andreas
    In this work, the technical applicability of biocatalytic phosphorus (P)-mobilization from plant residues and the subsequent conversion of mobilized P into fertilizer has been investigated. Initially, P organically bound to phytate, is liberated by intrinsic and exogenous phytase enzymes. By conditioning plant residues prior to feeding, the enzymatic P-mobilization aims to generate high value feed material and promote a sustainable P-management. Rye bran, a by-product of the milling industry known for its high phytate content, is used as a model substrate in this research. To monitor and evaluate the P-mobilization rate, an inline process analysis based on Fourier-Transform-Infrared spectroscopy was established. The developed inline analytical approach experienced a root mean squared error of prediction of 81 mgP∙100gbran-1, corresponding to a deviation of about 8% with respect to the total phytate content in rye bran. Using this approach, it is shown that metabolically induced germination activates intrinsic phytate hydrolyzing enzymes. Maximum intrinsic activity was identified at 43 °C, pH 5.3, and a bran to water ratio of 1 to 7 (w/v). Under these conditions, most of the phytate present was degraded within 30 min at a rate of 5565 U∙kgbran-1. For maximum P-mobilization, an exogenously applied phytase blend consisting of rPhyXT52 phytase and the phytase from D. castelli was used. Kinetic studies on the phytase blend demonstrated its suitability for batch operation. The P-mobilization process achieved complete elimination of phytate, resulting in a 90% reduction of the total P-content across different scales up to 400 L reactions. Supportive ultrasound as well as enzymatic treatment of the cellular matrix substantially increased the P-mobilization rate by over 90%. Among the enzyme formulations tested, xylanases showed the most pronounced effect. Struvite precipitation from the process wastewater containing the mobilized P achieved 99% P-recovery with over 90% purity at pH 9, 20 °C, and an equimolar input ratio of constitution ions. The results and observations indicate a very robust process and underline the feasibility and applicability of enzymatic P-mobilization and struvite precipitation for P-recovery on a larger scale. The production of value-added feed material through phytate depletion and utilization of phytate bound P in renewable resources contributes to a more resilient P-bioeconomy.
    Publicationtype: Doctoral Thesis
      55  32
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    Item type:Publication, Access status: with files ,
    From biomass to bioeconomy: engineering biocatalytic phosphorus mobilization from plant residues prior to animal feeding
    (2025)
    Widderich, Niklas Johannes Heinrich
    ;
    Liese, Andreas
    In this work, the technical applicability of biocatalytic phosphorus (P)-mobilization from plant residues and the subsequent conversion of mobilized P into fertilizer has been investigated. Initially, P organically bound to phytate, is liberated by intrinsic and exogenous phytase enzymes. By conditioning plant residues prior to feeding, the enzymatic P-mobilization aims to generate high value feed material and promote a sustainable P-management. Rye bran, a by-product of the milling industry known for its high phytate content, is used as a model substrate in this research. To monitor and evaluate the P-mobilization rate, an inline process analysis based on Fourier-Transform-Infrared spectroscopy was established. The developed inline analytical approach experienced a root mean squared error of prediction of 81 mgP∙100gbran-1, corresponding to a deviation of about 8% with respect to the total phytate content in rye bran. Using this approach, it is shown that metabolically induced germination activates intrinsic phytate hydrolyzing enzymes. Maximum intrinsic activity was identified at 43 °C, pH 5.3, and a bran to water ratio of 1 to 7 (w/v). Under these conditions, most of the phytate present was degraded within 30 min at a rate of 5565 U∙kgbran-1. For maximum P-mobilization, an exogenously applied phytase blend consisting of rPhyXT52 phytase and the phytase from D. castelli was used. Kinetic studies on the phytase blend demonstrated its suitability for batch operation. The P-mobilization process achieved complete elimination of phytate, resulting in a 90% reduction of the total P-content across different scales up to 400 L reactions. Supportive ultrasound as well as enzymatic treatment of the cellular matrix substantially increased the P-mobilization rate by over 90%. Among the enzyme formulations tested, xylanases showed the most pronounced effect. Struvite precipitation from the process wastewater containing the mobilized P achieved 99% P-recovery with over 90% purity at pH 9, 20 °C, and an equimolar input ratio of constitution ions. The results and observations indicate a very robust process and underline the feasibility and applicability of enzymatic P-mobilization and struvite precipitation for P-recovery on a larger scale. The production of value-added feed material through phytate depletion and utilization of phytate bound P in renewable resources contributes to a more resilient P-bioeconomy.
    Publicationtype: Doctoral Thesis
      27  10
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    Item type:Publication, Access status: with files ,
    Microwave-assisted acidic hydrolysis of phytate from rye bran – Experimental procedure and model prediction
    (Elsevier, 2023-11-01)
    Mayer, Natalie
    ;
    Dirauf, Martin P.
    ;
    Kaltschmitt, Martin
    Phytate is an abundant phosphorus (P) compound in plant material, which cannot be taken up by monogastric animals but is to a significant part released into the environment with excreta. In order to make use of cereals' phytate content, phytate hydrolysis by microwave-assisted thermal treatment of an acidic rye bran extract into inorganic phosphate was investigated experimentally and by modelling for process application. A phytate conversion of 98.5% could be achieved at 200 °C and 15 min reaction time and showed to be highly dependent on the temperature by a sigmoidal correlation. Treatment time showed its main influence in the mid temperature range (between 150 and 180 °C), thus didn't play a role anymore at beginning hydrolysis and towards full conversion. A mathematical quartic model represented phytate conversion with an optimum at harshest examined conditions and allows for predictions of the hydrolysis within the parameter range investigated. A kinetic model gives parameters of reaction order 0.68 and an activation energy of 118.7 kJ/mol with the option to predict phytate hydrolysis beyond the investigated parameter range and for varying input concentration. Equal liberation of all six phosphate groups from phytate is mechanistically suggested. Both model approaches show comparable results.
    Publicationtype: Journal Article
      42  64
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    Item type:Publication, Access status: without files ,
      53
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    Item type:Publication, Access status: without files ,
      44