Preparation and Preliminary Characterization of Alligator Mississippiensis Keratin-rich Extracts

The state of Louisiana has become the lead producer of alligator skins and meat in the United States. More than 300,000 alligators are harvested annually from farm and wild sources. Simultaneously, the industry generates thousands of pounds of waste during the processing of alligators. This waste contains valuable fibrous proteins such as keratins. This study aimed to identify keratin in keratin-rich extracts prepared from alligator backstraps. Alligator backstrap samples were collected from alligator processing facilities located in Springfield, Louisiana. The percentage of protein extracted with 2-mercaptoethanol (2BME), 2BME and dithiothreitol (DTT), DTT, or sodium metabisulfite (SMBS) was calculated. Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE), Matrix-assisted laser desorption ionization (MALDI), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electronic Microscopy (SEM) were used to characterize the AB keratin-rich extract. A multi-step process for the preparation of a keratin-rich extract from alligator backstraps was developed. Reduction with 200 mM dithiothreitol produced the greatest protein solubility (55%). A protein band of 10 kDa was observed when the buffer containing 200 mM DTT was used. The molecular weights (MW) of keratins determined by MALDI did not correlate with SDS-PAGE results suggesting that MALDI analysis was not optimized. FTIR spectra showed peaks for amide A, I, II, and III. The AB keratin-rich extract was rich in glycine and proline which is a characteristic of low-molecular-weight beta-keratins. The AB keratin-rich extract showed a flake-like network structure with some filaments, comparable to previous observations made on 10 kDa beta-keratin from poultry feather. The keratins contained in Alligator Mississippiensis offer a potential to improve waste management practices and increase revenue in the alligator industry, through their commercialization