Bioengineering

798 KiB

Open AccessArticle

Microbial Community Shifts during Biogas Production from Biowaste and/or Propionate

by Chaoran Li, Christoph Moertelmaier, Josef Winter and Claudia Gallert

Bioengineering 2015, 2(1), 35-53; https://doi.org/10.3390/bioengineering2010035 - 9 Feb 2015

Cited by 8 | Viewed by 6446

Propionate is the most delicate intermediate during anaerobic digestion as its degradation is thermodynamically unfavorable. To determine its maximum possible degradation rates during anaerobic digestion, a reactor was fed Monday to Friday with an organic loading rate (OLR) of 12/14 kg COD_biowaste·m⁻³·d⁻¹ plus propionate up to a final OLR of 18 kg COD·m⁻³·d⁻¹. No feed was supplied on weekends as it was the case in full-scale. To maintain permanently high propionate oxidizing activity (POA), a basic OLR of 3 kg COD_propionate·m⁻³·d⁻¹ all week + 11 kg COD_biowaste·m⁻³·d⁻¹ from Monday to Friday was supplied. Finally a reactor was operated with an OLR of 12 kg COD_biowaste·m⁻³·d⁻¹ from Monday to Friday and 5 kg COD_propionate·m⁻³·d⁻¹ from Friday night to Monday morning to maintain a constant gas production for permanent operation of a gas engine. The propionate degradation rates (PDRs) were determined for biowaste + propionate feeding. Decreasing PDRs during starvation were analyzed. The POA was higher after propionate supply than after biowaste feeding and decreased faster during starvation of a propionate-fed rather than a biowaste-fed inoculum. Shifts of the propionate-oxidizing and methanogenic community were determined. Full article

(This article belongs to the Special Issue Microbial Ecology of Anaerobic Digestion)

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796 KiB

Open AccessArticle

Electroactive Tissue Scaffolds with Aligned Pores as Instructive Platforms for Biomimetic Tissue Engineering

by John G. Hardy, R. Chase Cornelison, Rushi C. Sukhavasi, Richard J. Saballos, Philip Vu, David L. Kaplan and Christine E. Schmidt

Bioengineering 2015, 2(1), 15-34; https://doi.org/10.3390/bioengineering2010015 - 14 Jan 2015

Cited by 52 | Viewed by 10421

Abstract

Tissues in the body are hierarchically structured composite materials with tissue-specific chemical and topographical properties. Here we report the preparation of tissue scaffolds with macroscopic pores generated via the dissolution of a sacrificial supramolecular polymer-based crystal template (urea) from a biodegradable polymer-based scaffold (polycaprolactone, PCL). Furthermore, we report a method of aligning the supramolecular polymer-based crystals within the PCL, and that the dissolution of the sacrificial urea yields scaffolds with macroscopic pores that are aligned over long, clinically-relevant distances (i.e., centimeter scale). The pores act as topographical cues to which rat Schwann cells respond by aligning with the long axis of the pores. Generation of an interpenetrating network of polypyrrole (PPy) and poly(styrene sulfonate) (PSS) in the scaffolds yields electroactive tissue scaffolds that allow the electrical stimulation of Schwann cells cultured on the scaffolds which increases the production of nerve growth factor (NGF). Full article

(This article belongs to the Special Issue Biofabrication)

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815 KiB

Open AccessArticle

Label Free Detection of L-Glutamate Using Microfluidic Based Thermal Biosensor

by Varun Lingaiah Kopparthy, Siva Mahesh Tangutooru and Eric J. Guilbeau

Bioengineering 2015, 2(1), 2-14; https://doi.org/10.3390/bioengineering2010002 - 12 Jan 2015

Cited by 14 | Viewed by 7213

Abstract

A thermoelectric biosensor for the detection of L-glutamate concentration was developed. The thermoelectric sensor is integrated into a micro-calorimeter which measures the heat produced by biochemical reactions. The device contains a single flow channel that is 120 µm high and 10 mm wide with two fluid inlets and one fluid outlet. An antimony-bismuth (Sb-Bi) thermopile with high common mode rejection ratio is attached to the lower channel wall and measures the dynamic changes in the temperature when L-glutamate undergoes oxidative deamination in the presence of glutamate oxidase (GLOD). The thermopile has a Seebeck coefficient of ~7 µV·(m·K)⁻¹. The device geometry, together with hydrodynamic focusing, eliminates the need of extensive temperature control. Layer-by-layer assembly is used to immobilize GLOD on the surface of glass coverslips by alternate electrostatic adsorption of polyelectrolyte and GLOD. The impulse injection mode using a 6-port injection valve minimizes sample volume to 5 µL. The sensitivity of the sensor for glutamate is 17.9 nVs·mM⁻¹ in the linear range of 0–54 mM with an R² value of 0.9873. The lowest detection limit of the sensor for glutamate is 5.3 mM. Full article

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Open AccessEditorial

Acknowledgement to Reviewers of Bioengineering in 2014

by Bioengineering Editorial Ofiice

Bioengineering 2015, 2(1), 1; https://doi.org/10.3390/bioengineering2010001 - 9 Jan 2015

Cited by 1 | Viewed by 3795

Abstract

The editors of Bioengineering would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2014:[...] Full article

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Bioengineering, Volume 2, Issue 1 (March 2015) – 4 articles , Pages 1-53

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