We report the single-step derivatization reaction of a biopolymer based onL -lysine with D -biotin analogs:Co -poly(L -lysine)-graft-(ε-N -[X-D-biotinyl]-L -lysine) (PLL-X-Biotin). The valeric acid carboxylate of D -biotin is activated to an NHS ester for direct modification of amine groups in proteins and other macromolecules. NHS esters react by nucleophilic attack of an amine in the carbonyl group, releasing the NHS group, and forming a stable amide linkage. NHS-X-Biotin is the simplest biotinylation reagent commercially available. In contrast withD -biotin, it has a longer spacer arm off the valeric acid side chain allowing better binding potential for avidin or streptavidin probes. Derivatization of poly(L -lysine) (PLL) with NHS-X-Biotin led to a copolymer PLL-X-Biotin. UV-Visible, IR-FT and 1H NMR characteristics derived from synthesis are briefly discussed.

Electron transfer properties of the haem (FeIII/FeII) redox center, in human haemoglobin molecules, were investigated, in vitro, on glass/tin-doped indium oxide electrodes. The total surface concentration of electrochemically active haemoglobin molecules corresponded to a single protein monolayer. In addition, anodic and cathodic peak currents changed in direct proportion with the scan rate, suggesting a surface-controlled electrode process.

Propiedades de transferencia electrónica, del centro redox (FeIII/FeII) del grupo hemo, en moléculas de hemoglobina humana, fueron investigadas, in vitro, sobre electrodos de óxido de indio dopado con estaño. La concentración superficial total de moléculas de hemoglobina electroquímicamente activa correspondió a una monocapa de proteína sencilla. Además, las corrientes de pico anódica y catódica cambiaron en proporción directa con la velocidad de barrido, sugiriendo un proceso de electrodo controlado superficialmente.

The effect of real dairy wastewater (DWW) additions on the current density generated by a bioanode was evaluated in a half cell configuration under potentiostatic control, thus simulating the anodic chamber of a Microbial Fuel Cell. Low substrate additions increased current density up to 1655 ± 136 mA m−2, forming a two-current peak pattern. Then the system was tested with a casein-lactose synthetic media. A high protein concentration reduced the current density; individual compounds led to the highest current (330.5 mA m−2 with casein; 1276 mA m−2 with lactose). Moreover, the protein reduced the current start up time.

Se evaluó la densidad de corriente de un bioánodo con adiciones de agua residual lacto-alimenticia. A menor volumen de substrato adicionado, se observó mayor producción de densidad de corriente (1655 ± 136 mA m−2), con un patrón de dos picos de corriente. El sistema evaluado con un medio sintético de caseína-lactosa mostró que una alta concentración de proteína afectó negativamente la corriente producida; los componentes individuales generaron los valores más altos de corriente (330.5 mA m−2 con caseína; 1276 mA m−2 con lactosa). Adicionalmente la proteína favoreció el inicio de generación de corriente.