Organisms Commons^™

Reducing Equifinality Using Isotopes In A Process-Based Stream Nitrogen Model Highlights The Flux Of Algal Nitrogen From Agricultural Streams, William I. Ford, James F. Fox, Erik Pollock

Biosystems and Agricultural Engineering Faculty Publications

The fate of bioavailable nitrogen species transported through agricultural landscapes remains highly uncertain given complexities of measuring fluxes impacting the fluvial N cycle. We present and test a new numerical model named Technology for Removable Annual Nitrogen in Streams For Ecosystem Restoration (TRANSFER), which aims to reduce model uncertainty due to erroneous parameterization, i.e., equifinality, in stream nitrogen cycle assessment and quantify the significance of transient and permanent removal pathways. TRANSFER couples nitrogen elemental and stable isotope mass‐balance equations with existing hydrologic, hydraulic, sediment transport, algal biomass, and sediment organic …

Evaluation Of Flocculation, Sedimentation, And Filtration For Dewatering Of Scenedesmus Algae, Nicholas A. Rhea, Jack Groppo, Czarena Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Algae can be used as a feedstock for agricultural fertilizers, livestock and poultry feeds, anaerobic digestion, and biofuel production. For each end product, the requirements for moisture content (or solids content) vary, such that a desirable water removal strategy needs to be adaptable to varying levels of water removal. Flocculation, sedimentation, and filtration were evaluated as possible strategies for thickening and dewatering of algae. The goal of this study was to validate that algae cells treated by such means could be processed by vacuum belt filters and to determine the conditions under which the solids content could be increased to …

The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson

Biosystems and Agricultural Engineering Faculty Publications

Phanerochaete chrysosporium treatment is less effective as a biological pretreatment on feedstock with larger particle sizes. We hypothesized that the improved effectiveness of the pretreatment when smaller particle sizes are used may be due to the inherently higher bulk density with smaller particle sizes. The effects of substrate bulk density and particle size on the efficacy of P. chrysosporium pretreatment of switchgrass (Panicum virgatum) was tested experimentally. Phanerochaete chrysosporium was grown on senesced switchgrass (2 different particle sizes) with various bulk densities. In all treatments, the fungal-pretreated samples released more glucose during enzymatic saccharification than the control sample. …

First Proof Of Concept Of Sustainable Metabolite Production From High Solids Fermentation Of Lignocellulosic Biomass Using A Bacterial Co-Culture And Cycling Flush System, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

To improve the lignocellulose conversion for ABE in high solids fermentation, this study explored the feasibility of cycling the process through the cellulolytic or/and solventogenic phases via intermittent flushing of the fermentation media. Five different flushing strategies (varying medium ingredients, inoculum supplement and cycling through phases) were investigated. Flushing regularly throughout the cellulolytic phase is necessary because re-incubation at 65 °C significantly improved glucose availability by at least 6-fold. The solvents accumulation was increased by 4-fold using corn stover (3-fold using miscanthus) over that produced by flushing only through the solventogenic phase. In addition, cycling process was simplified by re-incubating …

Phanerochaete Chrysosporium Pretreatment Of Biomass To Enhance Solvent Production In Subsequent Bacterial Solid-Substrate Cultivation, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

This study investigated pretreatment of corn stover using solid substrate cultivation (SSC) of Phanerochaete chrysosporium (P. chrysosporium) to improve subsequent accessibility to cellulose. Thereafter, Clostridium thermocellum (C. thermocellum) was directly inoculated onto the pretreated biomass to accomplish hydrolysis, followed by solventogenesis by introducing Clostridium beijerinckii (C. beijerinckii).

An enzyme suite containing laccase, lignin peroxidase and manganese peroxidase activity was detected during the cultivation of P. chrysosporium on corn stover within 288 h at an initial moisture content 𝓌_H2O = 80% (mass of water/total mass). Incubation factors, such as substrate moisture content and cultivation …

Pretreatment Of Scenedesmus Sp. Biomass As A Potential Anaerobic Digestion Substrate, Xinyi E, Czarena Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Algal biomass can be a potential substrate for anaerobic digestion. However, raw algae cells show a resistance to biological degradation, resulting in a slower methane production rate. Varying thermal and chemical pretreatments of algal biomass were investigated in an attempt to increase soluble organic matter (SOM) yield, which would result in enhanced methane production during subsequent anaerobic digestion. Scenedesmus sp. was harvested using three different procedures: with flocculation, with flocculation and drying, and without flocculation or drying. For all pretreatments and algae types, fluorescence micrographs were obtained to visually confirm the degradation of the algal cell walls. A complete 2 …

Influence Of Media Composition On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus Utilized For Co2 Mitigation, Czarena L. Crofcheck, Xinyi E, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews

Biosystems and Agricultural Engineering Faculty Publications

Atmospheric carbon dioxide levels have increased since the industrial revolution due to increasing combustion of fossil fuels. One possible CO₂ mitigation strategy is the use of microalgae for mitigation of CO₂. This paper focuses on the influence of media composition on the growth rate of two microalgae strains, Chlorella vulgaris and Scenedesmus actus. A KNO₃ based medium was found to work better for Chlorella, while a urea based equivalent worked better for Scenedesmus. The urea based media investigated here resulted in growth similar to that found with previously reported KNO₃ based media. …

Influence Of Flue Gas Components On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus, Czarena Crofcheck, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews

Biosystems and Agricultural Engineering Faculty Publications

Atmospheric carbon dioxide levels have increased since the industrial revolution due to the increase in combustion of fossil fuels. One possible alternative strategy is the use of microalgae for CO₂ capture and recycling. Major components in coal-derived flue gas that may accumulate and effect algae growth include both sulfur oxides and fly ash. However, in practical application, sulfur oxides will be converted quickly to the acid product (H₂SO₄) in the aerobic aqueous conditions of algae cultivation. In this article, the influence of elevated H₂SO₄ levels and the presence of coal-derived fly ash …

Submerged And Solid-State Phytase Fermentation By Aspergillus Niger: Effects Of Agitation And Medium Viscosity On Phytase Production, Fungal Morphology And Inoculum Performance, Maria Papagianni, Sue E. Nokes, Keith Filer

Biosystems and Agricultural Engineering Faculty Publications

Qualitative relationships between agitation levels and medium viscosity, Aspergillus niger morphology and phytase production were investigated in submerged and solid-state fermentations. Overall phytase production increased with increasing shaker speeds from 150 to 300 rpm, although specific growth rates and phytase production rates were higher at 150 rpm for 72 h from inoculation. Fungal morphology was greatly influenced by agitation with the morphological forms of small pellets and entangled mycelia predominating at 150 rpm, while the free filamentous form was obtained at 300 rpm. Upon inoculation of SSF, increased productivities were obtained from inocula grown at 150 rpm. A shift towards …

Indicator Bacteria Concentrations Of Two Northwest Arkansas Streams In Relation To Flow And Season, Dwayne R. Edwards, Mark S. Coyne, Tommy C. Daniel, P. F. Vendrell, J. F. Murdoch, P. A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Concentrations of indicator bacteria such as fecal coliform (FC) and fecal streptococcus (FS) are often used to assess the suitability of waters for their intended use(s) and to allocate resources for water quality improvement measures. There is evidence, however, that concentrations of FC and FS can be influenced by variables such as season and flow rate during sampling, which could lead to biased results. The objective of this study was to assess the impacts of season and flow rate on concentrations of FC and FS. Fecal indicator bacteria concentrations were measured for approximately three years at five sites on two …