Biodegradation of coffee pulp tannin by Penicillium verrucosum for production of tannase, statistical optimization and its application

• Molecular characterization of potent fungal tannase producer.
• Tannase production by SSF on coffee pulp by Penicillium verrucosum.
• Statistical optimization for maximum tannase productivity, 115.995 U/g coffee pulp.
• Tannase treatment on fruit juice to reduce the bitterness and astringency.

Coffee pulp is a primary by-product produced during coffee processing and represents 30% of the coffee fruit on a dry-weight basis. A novel potential tannin degrading fungi was isolated from coffee by-products. Among the various fungi isolated, Penicillium sp. CFR303 was found to be potent with 66.5 ± 0.9% tannin degradation. The potent tannin degrader was identified as Penicillium verrucosum using internal transcribed spacer's (ITS) −5.8S rDNA analysis. Solid state fermentation was carried out on coffee pulp as a sole carbon source and yielded 28.173 ± 1.4 U/gds of tannase. Further, 3.93 fold increase in tannase production (115.995 U/gds) was achieved using central composite rotatable design, a statistical approach. Model validations showed excellent agreement between the experimental results and the predicted responses with a confidence level of 95%. Coffee pulp accounts to 8–10% tannin content and the present study demonstrates coffee pulp as an excellent substrate for production of value added products. Aonla and pomegranate juice were treated with partially purified tannase and the degradation of tannins was evident by changes in the physicochemical parameters of the juice. Thus, the present investigation signifies utilization of coffee pulp for production of tannase as value addition and its potential application in the food industry.