Figure 1

Enzymatic hydrolysis of feather keratin by microbial keratinases is characterized, showing protein fragment profiles. The Bacillus subtilis-derived keratinase produces low molecular weight hydrolysates suitable for hair care applications.

Figure 2

Molecular weight distribution of the keratin hydrolysates is analyzed, comparing enzymatic products with commercial alternatives. Lower molecular weight peptides penetrate hair fibers more effectively, offering superior protection against chemical and environmental damage.

Figure 3

MALDI-TOF mass spectrometry analysis compares enzymatic keratin hydrolysates from Bacillus subtilis with a commercial hydrolysate (KH1). The mass spectra reveal distinct peptide profiles, with the enzymatic product showing a different molecular weight distribution pattern.

Figure 5

Scanning electron microscopy reveals the surface morphology of colored hair before and after treatment with enzymatic keratin hydrolysates. Treated hair shows smoother cuticle surfaces compared to untreated controls, indicating the hydrolysate's protective and restorative properties following heat styling at 180 degrees Celsius.

Figure 6

SEM micrographs compare colored and straightened hair treated with enzymatic keratin hydrolysates against controls. The cuticle damage from chemical coloring and heat straightening appears reduced in treated samples, suggesting the hydrolysate provides a protective barrier.

Figure 7

Electronic scanning microscope images show bleached hair before and after enzymatic hydrolysate treatment, with and without heat application. Black arrows indicate areas of cuticle repair where the protein hydrolysate has filled surface defects caused by bleaching.