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Al-Kharousi ZS, Al-Ramadhani Z, Al-Malki FA, Al-Habsi N. Date Vinegar: First Isolation of Acetobacter and Formulation of a Starter Culture. Foods 2024; 13:1389. [PMID: 38731760 PMCID: PMC11083709 DOI: 10.3390/foods13091389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/11/2024] [Accepted: 04/27/2024] [Indexed: 05/13/2024] Open
Abstract
There is a lack of scientific analysis and control over the production of date vinegar in Oman, despite its growing demand in the worldwide market. Traditional production of date vinegar may lead to elevated amounts of ethanol (≥0.5%) and reduced content of acetic acid (<4%) compared to the standard acceptable levels. This study aimed to isolate non-Gluconobacter species from date vinegar produced by spontaneous fermentation and formulate starter cultures for quick and efficient production of date vinegar. In spontaneous fermentation date vinegar samples, the highest concentration of acetic acid was 10.42% on day 50. Acetobacter malorum (5 isolates), A. persici (3 isolates), and A. tropicalis (3 isolates) were identified based on 16S rRNA gene sequences for the first time in date vinegar. For date vinegar prepared with a starter culture of Acetobacter and yeast, the highest concentration of acetic acid was 4.67%. In conclusion, spontaneous fermentation resulted in the production of date vinegar with a high concentration of acetic acid, acceptable concentrations of ethanol and methanol, and the first isolation of three Acetobacter species. The formulated starter culture produced acceptable amounts of acetic acid and the time of fermentation was reduced 10 times (from 40 days to 4 days). This can provide the basis for producing a personalized or commercial product that ensures the production of good-quality date vinegar in an easier, faster, safer, and more efficient way from low-quality and surplus dates.
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Affiliation(s)
- Zahra S. Al-Kharousi
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box 34, Al-Khod 123, Oman; (Z.A.-R.); (F.A.A.-M.); (N.A.-H.)
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Tanakura Y, Uekawa Y, Shige Y, Fukuda W, Ikuta S, Wu HN, Yasukawa K, Yanagihara I, Fujiwara S. Expression of a recombinant protein by an acetic acid bacterial host. J Biotechnol 2024; 380:38-50. [PMID: 38135188 DOI: 10.1016/j.jbiotec.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
We evaluated the suitability of Komagataeibacter europaeus, a vinegar production organism adept at synthetic media growth, as a host for heterologous gene expression. Cryptic plasmids (pGE1 and pGE2 derivatives) from K. europaeus strain KGMA0119 were employed as vectors for heterologous gene expression. The focus was placed on the groES promoter as a potential inducible switch. The groES promoter was fused with the EGFP gene and introduced into a pGE1 derivative to assess its suitability. Ethanol, acetic acid, and heat stresses were examined under various conditions for induction. EGFP transcription surged 600-fold when late logarithmic phase K. europaeus cells, cultured at 30 °C, endured heat stress at 40 °C, coupled with 20% acetic acid and 30% ethanol stress after an additional 6-hour cultivation. This robust induction system was then applied to express two proteins, Tth pol from the thermophilic bacterium Thermus thermophilus strain M1 and UPV230, a restriction enzyme from the acid-tolerant microorganism Ureaplasma parvum, known to cause vaginal infections and miscarriages. Both Tth pol and UPV230 were successfully expressed in K. europaeus cells and purified. The recovery of Tth pol from K. europaeus cells (480 µg protein per liter culture) was approximately half that from E. coli (960 µg protein per liter culture). In contrast, UPV230 recovery from K. europaeus cells (640 µg protein per liter culture) was nearly 10 times higher than that from Escherichia coli (66 µg protein per liter). The data highlights the potential of acetic acid bacteria as a host for producing acidophilic proteins. The shift in recognition from a 6-base sequence to a 4-base sequence of UPV230 was observed, accompanied by a change in structure as the pH transitioned from acidic pH to near-neutral pH.
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Affiliation(s)
- Yuya Tanakura
- Department of Biosciences, Graduate School of Science and Technology, Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan
| | - Yasuyoshi Uekawa
- Department of Biosciences, Graduate School of Science and Technology, Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan
| | - Yuki Shige
- Department of Biosciences, Graduate School of Science and Technology, Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan
| | - Wakao Fukuda
- Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan
| | - Soichiro Ikuta
- Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan
| | - Heng Ning Wu
- Department of Developmental Medicine, Research Institute, Osaka Women's and Children's Hospital, Izumi, Osaka 594-1101, Japan
| | - Kiyoshi Yasukawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Itaru Yanagihara
- Department of Developmental Medicine, Research Institute, Osaka Women's and Children's Hospital, Izumi, Osaka 594-1101, Japan
| | - Shinsuke Fujiwara
- Department of Biosciences, Graduate School of Science and Technology, Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan; Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, 1 Gakuen-Uegahara, Sanda, Hyogo 669-1330, Japan.
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