Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 18, 2005
Publication Date: January 1, 2006
Citation: Barone, J.R., Schmidt, W.F. 2006. Effect of formic acid exposure on Keratin fiber derived from poultry feather biomass. Bioresource Technology. 97(2):233-242.
Interpretive Summary: This paper describes a method to make a pesticide delivery system out of feather keratin, previously considered a waste material. The pesticide is formic acid which is used to control Varroa mites. This is imperative as these mites have built a resistance to other currently used pesticides.
In this study, the diffusion kinetics of formic acid into and out of keratin feather fiber, obtained from poultry feather biomass, are studied using absorption/desorption experiments. Two Fickian regions are observed during absorption, a fast absorption of formic acid followed by a region of slower absorption. There does not appear to be saturation of the keratin with formic acid. After very long times, i.e., >103 hours, the absorption experiments are stopped, and the formic acid is allowed to desorb from the keratin material. The desorption kinetics of formic acid out of the keratin fiber do not mirror the absorption kinetics, indicating a change in the keratin microstructure. Differential scanning calorimetry (DSC) analysis on the keratin feather fiber before and after absorption experiments and following desorption experiments shows a reduction in the crystalline melting peak of the keratin feather fiber upon formic acid exposure. This indicates that the crystallinity is disrupted, resulting in more amorphous fraction in the keratin polymer. The increase in the amorphous fraction explains the faster desorption kinetics over the absorption kinetics.