Proteolytic system ofBacillussp. CL18 is capable of extensive feather degradation and hydrolysis of diverse protein substrates

Abstract

1. Feathers are recalcitrant protein-rich wastes produced in huge amounts by poultry processing for meat production. Hence, feather bioconversion and protease production by Bacillus sp. CL18 were investigated. 2. Bacillus sp. CL18 demonstrated a remarkable feather-degrading potential. Through cultivations on feather broth (10 g l feathers), 94.5% ± 3% of whole feathers were degraded after 4 d. Increases in soluble protein contents were observed and protease production was maximal also at d 4. This strain produced diverse proteolytic enzymes during growth. 3. Crude protease displayed optimal activity at 55°C (50-62°C), pH 8.0 (7.0-9.0) and a low thermal stability. Proteolytic activity increased in the presence of Ca, Mg, Triton X-100, Tween 20 and dimethyl sulphoxide. Inhibition profile indicated that crude protease contains, mainly, serine proteases. Enzyme preparation hydrolysed mainly casein and soy protein isolate. 4. The keratinolytic capacity of Bacillus sp. CL18 at moderate temperatures (30°C) might be appropriate for feather conversion, resulting in protein hydrolysates and proteolytic enzymes. Proteases are postulated to be added-value products that can be obtained from such a bioprocess.

Bacillus sp. FPF-1 Produced Keratinase with High Potential for Chicken Feather Degradation

“…In no small degree of certainty, it would be safe to indicate that the isolates produced keratinases [11]. Keratin-degrading efficiency of the test bacteria may be a reflection of the effectiveness of the extracellular keratinase produced; and the bacterial isolates under investigation showed consistency in that regard [12].…”

Cohnella 1759 cysteine protease shows significant long term half-life and impressive increased activity in presence of some chemical reagents

“…As shown in Table 3. β-ME had the opposite effect on rEla in comparison with other cysteine proteases and inhibited the protease slightly at the concentration of 2 mM, however reduced the enzyme activity to 20% at higher concentration (5 mm) suggesting the importance of disulfide bonds in preserving rEla active conformation 58 . In addition, the enzyme was inhibited by EDTA to the extent of 56% and 40% at 2 mm and 5 mm concentration, respectively.…”

Thermoactive metallo-keratinase from Bacillus sp. NFH5: Characterization, structural elucidation, and potential application as detergent additive

“…This observation thus highlights the relevance of strain NFH5 in converting keratinous residues into bio-accessible protein units. The protein concentration pattern suggests that microbial keratinase liberated more soluble proteins from chicken feather keratin during fermentation [ 46 ]. The drift of medium pH from the acidic to an alkaline range indicates the possible presence of ammonia in the production medium [ 47 ].…”