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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 feedingIn 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 Thesis55 32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , An up-scaled biotechnological approach for phosphorus-depleted rye bran as animal feed(Springer, 2024-05-13); ; ; ; Side streams from the milling industry offer excellent nutritional properties for animal feed; yet their use is constrained by the elevated phosphorus (P) content, mainly in the form of phytate. Biotechnological P recovery fosters sustainable P management, transforming these streams into P-depleted animal feed through enzymatic hydrolysis. The enzymatic P mobilization not only enables P recovery from milling by-products but also supports the valorization of these streams into P-depleted animal feeds. Our study presents the scalability and applicability of the process and characterizes the resulting P-depleted rye bran as animal feed component. Batch mode investigations were conducted to mobilize P from 100 g to 37.1 kg of rye bran using bioreactors up to 400 L. P reductions of 89% to 92% (reducing from 12.7 gP/kg to 1.41–1.28 gP/kg) were achieved. In addition, High Performance Ion Chromatography (HPIC) analysis showed complete depletion of phytate. The successful recovery of the enzymatically mobilized P from the process wastewater by precipitation as struvite and calcium hydrogen phosphate is presented as well, achieving up to 99% removal efficiency. Our study demonstrates a versatile process that is easily adaptable, allowing for a seamless implementation on a larger scale. Graphical Abstract: (Figure presented.).Publicationtype: Journal Article17 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Online monitoring of phytate content in plant residuals during wet-treatmentThe occurrence of organically bound phosphorus (P) as phytate in plant-based feeding material is a challenge for livestock farming due to limited utilization during the digestion by the animal. Its excretion into the environment through the manure pathway, poses a challenge, due to increased eutrophication and restrictions for P. Hence, while the routine supplementation of phytase enzymes in monogastric diets is common practice, metabolically triggering endogenous plant enzymes by wet-treatment prior to feeding can also lead to a better utilization of phytate bound P and increased digestibility by the animal. Nonetheless, traditional quantification of residual phytate content in plant material is both labor- and chemical-intense. The aim of this study is, therefore, to predict the remaining phytate content during wet-treatment through a straightforward and flexible methodological approach based on real-time analysis. For this, rye bran is used as a model substrate. A partial least squares regression algorithm relates the infrared spectra to the concentrations and predict the amount of P species that are transferred from the bran matrix to the liquid phase. By applying a mass balance for P and considering the effect of water compression, the amount of residual phytate content in rye bran at different time points of wet-treatment is determined. Results are compared to wet chemical methods, resulting in a RMSEP of 0.28 gphytate∙100 gbran−1. In addition, the study demonstrates the feasibility of this approach and provides insights into phytate degradation in plant residuals. The method holds the potential for further applications for the screening and investigation of feed material conditioning and also offers the possibility to employ various real-time analytical techniques for assessing phytate remnants in biological samples during wet-treatment.Publicationtype: Journal Article14 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Comparison of phosphorus and phytase activity distribution in wheat, rye, barley and oats and their impact on a potential phytate separation(Springer, 2023-01-03); ; ; ; When facing today’s scarcity of mineral phosphorus (P) resources and the environmental issues following enhanced P losses especially from agriculture, new solutions need to be implemented. In this framework, the potential for a mechanical separation of a P rich grain fraction from wheat, rye, barley and oats is investigated in order to provide animal feed with reduced organic P content. Thus, P accumulation in manure and soils should be prevented. Also, the subsequent utilization of the separated organic P, which occurs in the form of inositol P, for a sustainable P management via activation of intrinsic enzymes is evaluated. It was shown that in grain layers at 7.0, 5.5, 6.4 and 2.5% cross section of wheat, rye, barley and oats, respectively, maximum inositol P occurs with 1.6, 0.8, 1.4 and 1.2 g/100 g. Phytase activity is also highest in the outer layers of the grains with maxima of 9300, 12,000, 8400 and 2400 U/kg, respectively. A removal of the specific layers where inositol P is accumulated could possibly achieve a 24, 31, 60 and 27% organic P reduction for wheat, rye, barley and oats with 7, 14, 25 or 7% grain elimination. A debranning, eliminating all the outer grain layers to a certain extent, in contrast, leads to significantly higher mass losses. Within the P enriched layer determined from inositol P distribution, phytase activity is calculated to be around 285, 831, 777 and 42 U/kg for wheat, rye, barley and oats, respectively.Publicationtype: Journal ArticleScopus© Citations 1 96 181 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Control of redox potential in a novel continuous bioelectrochemical system led to remarkable metabolic and energetic responses of Clostridium pasteurianum grown on glycerol(BioMed Central, 2022-09-01); ; ; ; BACKGROUND: Electro-fermentation (EF) is an emerging tool for bioprocess intensification. Benefits are especially expected for bioprocesses in which the cells are enabled to exchange electrons with electrode surfaces directly. It has also been demonstrated that the use of electrical energy in BES can increase bioprocess performance by indirect secondary effects. In this case, the electricity is used to alter process parameters and indirectly activate desired pathways. In many bioprocesses, oxidation-reduction potential (ORP) is a crucial process parameter. While C. pasteurianum fermentation of glycerol has been shown to be significantly influenced electrochemically, the underlying mechanisms are not clear. To this end, we developed a system for the electrochemical control of ORP in continuous culture to quantitatively study the effects of ORP alteration on C. pasteurianum by metabolic flux analysis (MFA), targeted metabolomics, sensitivity and regulation analysis. RESULTS: In the ORP range of -462 mV to -250 mV, the developed algorithm enabled a stable anodic electrochemical control of ORP at desired set-points and a fixed dilution rate of 0.1 h-1. An overall increase of 57% in the molar yield for 1,3-propanediol was observed by an ORP increase from -462 to -250 mV. MFA suggests that C. pasteurianum possesses and uses cellular energy generation mechanisms in addition to substrate-level phosphorylation. The sensitivity analysis showed that ORP exerted its strongest impact on the reaction of pyruvate-ferredoxin-oxidoreductase. The regulation analysis revealed that this influence is mainly of a direct nature. Hence, the observed metabolic shifts are primarily caused by direct inhibition of the enzyme upon electrochemical production of oxygen. A similar effect was observed for the enzyme pyruvate-formate-lyase at elevated ORP levels. CONCLUSIONS: The results show that electrochemical ORP alteration is a suitable tool to steer the metabolism of C. pasteurianum and increase product yield for 1,3-propanediol in continuous culture. The approach might also be useful for application with further anaerobic or anoxic bioprocesses. However, to maximize the technique's efficiency, it is essential to understand the chemistry behind the ORP change and how the microbial system responds to it by transmitted or direct effects.Publicationtype: Journal ArticleScopus© Citations 6 70 104 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Conditioning of Feed Material Prior to Feeding: Approaches for a Sustainable Phosphorus Utilization(Multidisciplinary Digital Publishing Institute (MDPI), 2022-03-28); ; ; ; A circular phosphorus (P) bioeconomy is not only worthwhile for conserving limited mineral P reservoirs, but also for minimizing negative environmental impacts caused by human-made alterations. Although P is an essential nutrient, most of the P in concentrates based on cereals, legumes and oilseed byproducts is organically bound to phytate. The latter cannot be efficiently utilized by monogastric animals and is therefore diluted into the environment through the manure pathway. This review examines various strategies for improved P utilization in animals and reflects the respective limitations. The strategies considered include feeding of debranned feedstuffs, pre-germinated feed, co-feeding of phytase and feeding material with high native phytase activity. All these approaches contribute to an improved P bioavailability. However, about half of the organic P content continues to be excreted and therefore remains unused by the animals. Nevertheless, technologies for an efficient utilization of P from cereal-based feed already exist; however, these are not industrially established. Conditioning feed material prior to feeding fosters P-reduced feed; meanwhile, P bound to phytate can be recovered. Based on known techniques for P separation and solubilisation from cereal products and phytate conversion, potential designs for feed material conditioning processes are proposed and evaluated.Publicationtype: Journal ArticleScopus© Citations 6 89 192