1
|
Xin WG, Li XD, Zhou HY, Li X, Liu WX, Lin LB, Wang F. Isolation, antibacterial characterization, and alternating tangential flow-based preparation of viable cells of Lacticaseibacillus paracasei XLK 401: Potential application in milk preservation. J Dairy Sci 2024; 107:1355-1369. [PMID: 37776999 DOI: 10.3168/jds.2023-23622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 09/08/2023] [Indexed: 10/02/2023]
Abstract
It is desirable to obtain high levels of viable Lacticaseibacillus paracasei, a widely used food probiotic whose antibacterial activity and potential application in milk remain largely uninvestigated. Here, we isolated and purified the L. paracasei strain XLK 401 from food-grade blueberry ferments and found that it exhibited strong antibacterial activity against both gram-positive and gram-negative foodborne pathogens, including Staphylococcus aureus, Salmonella paratyphi B, Escherichia coli O157, and Shigella flexneri. Then, we applied alternating tangential flow (ATF) technology to produce viable L. paracasei XLK 401 cells and its cell-free supernatant (CFS). Compared with the conventional fed-batch method, 22 h of ATF-based processing markedly increased the number of viable cells of L. paracasei XLK 401 to 12.14 ± 0.13 log cfu/mL. Additionally, the CFS exhibited good thermal stability and pH tolerance, inhibiting biofilm formation in the abovementioned foodborne pathogens. According to liquid chromatography-mass spectrometry analysis, organic acids were the main antibacterial components of XLK 401 CFS, accounting for its inhibition activity. Moreover, the CFS of L. paracasei XLK 401 effectively inhibited the growth of multidrug-resistant gram-positive Staph. aureus and gram-negative E. coli O157 pathogens in milk, and caused a reduction in the pathogenic cell counts by 6 to 7 log cfu/mL compared with untreated control, thus considerably maintaining the safety of milk samples. For the first time to our knowledge, ATF-based technology was employed to obtain viable L. paracasei on a large scale, and its CFS could serve as a broad-spectrum biopreservative for potential application against foodborne pathogens in milk products.
Collapse
Affiliation(s)
- Wei-Gang Xin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China
| | - Xin-Dong Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China
| | - Huan-Yu Zhou
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China
| | - Xin Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China
| | - Wei-Xin Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China
| | - Lian-Bing Lin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China.
| | - Feng Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, Kunming, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Yunnan, Kunming, 650500, China.
| |
Collapse
|
2
|
Setianto S, Men LK, Bahtiar A, Panatarani C, Joni IM. Carbon quantum dots with honeycomb structure: a novel synthesis approach utilizing cigarette smoke precursors. Sci Rep 2024; 14:1996. [PMID: 38263381 PMCID: PMC10806174 DOI: 10.1038/s41598-024-52106-3] [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: 11/14/2023] [Accepted: 01/13/2024] [Indexed: 01/25/2024] Open
Abstract
This study presents a novel approach to synthesizing honeycomb carbon quantum dots (CQDs) from cigarette smoke by a hydrothermal process. A comprehensive characterization of these CQDs, conducted through high-resolution transmission electron microscopy (HRTEM), showcases their unique honeycomb structure, with an average particle size of 6.3 nm. Photoluminescence (PL) in CQDs is a captivating phenomenon where these nanoscale carbon structures emit strong blue luminescence at 461 nm upon exposure to ultraviolet light, with their excitation peak occurring at 380 nm. Fourier Transform Infrared (FTIR) analysis also identifies specific functional groups within the CQDs, offering valuable insights into the mechanisms governing their photoluminescence. Analysis of excitation spectra indicates the presence of both aromatic C=C bonds at 254 nm and C-O bonds from 280 to 420 nm.
Collapse
Affiliation(s)
- Setianto Setianto
- Department of Physics, FMIPA, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Sumedang, 45363, Jawa Barat, Indonesia.
- Functional Nano Powder University Centers of Excellence, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Jatinangor, 45363, Jawa Barat, Indonesia.
| | - Liu Kin Men
- Department of Physics, FMIPA, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Sumedang, 45363, Jawa Barat, Indonesia
| | - Ayi Bahtiar
- Department of Physics, FMIPA, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Sumedang, 45363, Jawa Barat, Indonesia
| | - Camellia Panatarani
- Department of Physics, FMIPA, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Sumedang, 45363, Jawa Barat, Indonesia
- Functional Nano Powder University Centers of Excellence, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Jatinangor, 45363, Jawa Barat, Indonesia
| | - I Made Joni
- Department of Physics, FMIPA, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Sumedang, 45363, Jawa Barat, Indonesia
- Functional Nano Powder University Centers of Excellence, Padjadjaran University, Jl. Raya Bandung-Sumedang KM 21, Jatinangor, 45363, Jawa Barat, Indonesia
| |
Collapse
|