Comparative Evaluation on Tannase Production by Lasiodiplodia plurivora ACN-10 under Submerged Fermentation (SmF) and Solid State Fermentation (SSF)

Abstract

Aim: Tannase (tannin acyl hydrolase, E.C. 3.1.1.20) catalyzes the hydrolysis of ester bonds from complex hydrolysable tannins with the production of gallic acid and glucose and possess broad applications in biotechnology. This study is aimed at the production of tannase by Lasiodiplodia plurivora ACN-10 in SmF and SSF using Terminalia cattapa (almond leaves) and Magnifera indica (mango leaves) as substrates. Study Design: The design adopted to evaluate the production of tannase is submerged (SmF) and solid state (SSF) fermentation. Study Area: Federal Institute of Industrial Research Oshodi, Lagos State Nigeria. Methodology: Fifteen different soil samples were indiscriminately collected within Oshodi, Lagos, Nigeria and were inoculated on PDA plates at 30°C for 3-5 days. A total of 30 isolates was screened on Czapek dox minimal agar incorporated with 1% tannic acid and plates were incubated for 96 h at 30°C. Fungal isolates which were able to disintegrate tannic acid produced a clear halo zone around the colony diameter and were selected to be positive for tannase activity. The best isolate was identified based on its morphological, microscopic and molecular characteristics. Thereafter production and extraction of tannase was carried out in SmF for 0-120 h and in SSF for 0-144 h using Terminalia cattapa (Almond leaves) and Magnifera indica (Mango leaves) as substrates. Results: The total fungal count ranged from 1.0×104 to 3.5×105 CFU/g. A total of 30 fungal isolates produced clear halo zones (ranging from 20 to 70 mm) around the colonies during the screening with tannic acid. Isolate ACN-10, which showed the highest tannic degradation was identified based on its morphological and microscopic characteristics. On the basis of 18S rRNA gene sequence studies, the isolate was identified as Lasiodiplodia plurivora strain ACN-10 and the sequence was submitted to the Genbank with the accession number: MG250374. Results obtained in this study indicated that both substrates can be used by the isolate for tannase production in both SmF and SSF. The result of our investigation on the use of Terminalia cattapa (almond leaves) and Magnifera indica (mango leaves) as substrates for tannase production showed that optimum yield (6.064 U/ml) was obtained at 120 h in SSF while optimum production (4.623 U/ml) was observed in SmF at 96 h using Terminalia cattapa as substrate. Conclusion: Results obtained from this study indicated higher tannase production in solid-state fermentation compared to submerged fermentation. This is the first report to the best of our knowledge that Lasiodiplodia plurivora strain is implicated in tannase secretion. The result also demonstrated high production of extracellular tannases from low cost substrates which can be optimized and scaled up for industrial processes.