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Saad MM, Saad AM, Hassan HM, Ibrahim EI, Abdelraof M, Ali BA. Optimization of tannase production by Aspergillus glaucus in solid-state fermentation of black tea waste. BIORESOUR BIOPROCESS 2023; 10:73. [PMID: 38647901 PMCID: PMC10991964 DOI: 10.1186/s40643-023-00686-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/08/2023] [Indexed: 04/25/2024] Open
Abstract
Tannases are valuable industrial enzymes used in food, pharmaceutical, cosmetic, leather manufacture and in environmental biotechnology. In this study, 15 fungal isolates were obtained from Egyptian cultivated soil and marine samples. The isolated fungi were qualitatively and quantitatively screened for their abilities to produce tannase. The selected fungal isolate NRC8 giving highest tannase activity was identified by molecular technique (18S rRNA) as Aspergillus glaucus. Among different tannin-containing wastes tested, the black tea waste was the best substrate for tannase production by Aspergillus glaucus in solid-state fermentation (SSF). Optimization of the different process parameters required for maximum enzyme production was carried out to design a suitable SSF process. Maximal tannase production was achieved with moisture content of 75%, an inoculums size of 6 × 108 spore/ml and sodium nitrate 0.2% (pH of 5.0) at 30 °C after 5 days of incubation. Box-Behnken experiment was designed to get a quadratic model for further optimization studies. Four-factor response-surface method with 27 runs was prepared using independent parameters including (moisture content %, initial pH, substrate concentration (g) and sodium nitrate concentration (g) for tannase model. The F- and P-values of the model were 4.30 and 0.002, respectively, which implied that the model is significant. In addition, the lack-of-fit was 1040.37 which indicates the same significance relative to the pure error. A. glaucus tannase was evaluated by the efficiency of conversion of tannic acid to gallic acid. Moreover, production of gallic acid from SSF process of A. glaucus using black tea waste was found to be 38.27 mg/ml. The best bioconversion efficiency was achieved at 40 °C with tannic acid concentration up to 200 g/L.
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Affiliation(s)
- Moataza Mahmoud Saad
- Microbial Chemistry Department, National Research Centre (NRC), 33 Bohouth St, Dokki, 12622, Giza, Egypt
| | - Abdelnaby Mahmoud Saad
- Microbial Chemistry Department, National Research Centre (NRC), 33 Bohouth St, Dokki, 12622, Giza, Egypt
| | - Helmy Mohamed Hassan
- Microbial Chemistry Department, National Research Centre (NRC), 33 Bohouth St, Dokki, 12622, Giza, Egypt
| | - Eman I Ibrahim
- Microbial Chemistry Department, National Research Centre (NRC), 33 Bohouth St, Dokki, 12622, Giza, Egypt.
| | - Mohamed Abdelraof
- Microbial Chemistry Department, National Research Centre (NRC), 33 Bohouth St, Dokki, 12622, Giza, Egypt.
| | - Basant A Ali
- Microbial Chemistry Department, National Research Centre (NRC), 33 Bohouth St, Dokki, 12622, Giza, Egypt
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