Production of dehairing protease by Bacillus cereus VITSN04: a model cradle-to-cradle approach for sustainable greener production of leathers

ABSTRACT

Despite several attempts over decades, process scalability and sustainability remain a challenge to produce an environmental-friendly enzyme to gain industrial attention. In the present study, microbial degradation of chrome shavings (chromium–collagen leather waste) and the resulting collagen hydrolysate for producing the dehairing protease by Bacillus cereus VITSN04 were investigated in a lab-scale fermentor. Scale-up degradation of shavings resulted in higher recovery of collagen hydrolysate (76%) within 72 h compared to shake flasks (68% in 120 h). Earlier achieved medium composition of collagen hydrolysate (12 g L⁻¹) and molasses (15 g L⁻¹) appeared to induce amylase at the high rate, despite the maximal production of protease (203.8 ± 0.18 U mL⁻¹), which was analysed by ANS fluorescence spectroscopy. Optimization of the media containing collagen hydrolysate (12 g L⁻¹) and molasses (5 g L⁻¹) was effective in producing protease (170.6 ± 0.1 U mL⁻¹) and reduced the co-synthesis of amylase (48.2 ± 0.09 U mL⁻¹). The controlled fermentation process by feeding molasses during the exponential growth phase had enhanced the dehairing protease production (∼2.96 fold). The produced protease then partitioned through the biphasic system and showed significant dehairing of goat skins on the pilot scale. Thus, the scalability of the process to produce dehairing enzymes using waste, generated at the site of its use, offers hope for sustainable greener production of leathers.

GRAPHICAL ABSTRACT

KEYWORDS:

• Dehairing protease
• Bacillus cereus VITSN04
• Chrome shavings
• Microbial degradation

Acknowledgement

We gratefully acknowledge the management of VIT, Vellore for providing us the common instrumentation facility.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Date availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

This work was supported by Department of Science and Technology(DST), India [grant number DST/TDT/WMT/2017/169].