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Nie M, Khalid F, Hu Q, Khalid A, Wu Q, Huang S, Wang Z. Site-Directed Mutagenesis: Improving the Acid Resistance and Thermostability of Bacillus velezensis α-Amylase and Its Preliminary Feed Application. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10487-10496. [PMID: 38683727 DOI: 10.1021/acs.jafc.4c01630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The current study aimed to improve the acid resistance and thermostability of Bacillus velezensis α-amylase through site-directed mutagenesis, with a specific focus on its applicability to the feed industry. Four mutation sites, P546E, H572D, A614E, and K622E, were designed in the C domain of α-amylase, and three mutants, Mut1 (E), Mut2 (ED), and Mut3 (EDEE), were produced. The results showed that the specific activity of Mut3 was 50 U/mg higher than the original α-amylase (Ori) after incubation at 40 °C for 4 h. Compared to Ori, the acid resistance of Mut3 showed a twofold increase in specific activity at pH 2.0. Moreover, the results of preliminary feed hydrolysis were compared between Ori and Mut3 by designing three factors, three levels of orthogonal experiment for enzymatic hydrolysis time, feed quantity, and amount of amylase. It was observed that the enzymatic hydrolysis time and feed quantity showed an extremely significant difference (p < 0.01) in Mut3 compared to Ori. However, the amount of enzyme showed significant (p < 0.05) improvement in the enzymatic hydrolysis in Mut3 as compared to Ori. The study identified Mut3 as a promising candidate for the application of α-amylase in the feed industry.
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Affiliation(s)
- Ming Nie
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
- School of Chemical and Biomolecular Engineering, Faculty of Engineering, The University of Sydney, Camperdown, NSW 2006, Australia
- School of Food and Bioengineering, Hefei University of Technology, Hefei 230009, Anhui, People's Republic of China
| | - Fatima Khalid
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
| | - Qian Hu
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
| | - Anam Khalid
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
| | - Qi Wu
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
| | - Shoujun Huang
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
| | - Zaigui Wang
- College of Life Science, Anhui Agricultural University, No. 130, Changjiang Road, Hefei 230036, Anhui, People's Republic of China
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Lu Y, Xing S, He L, Li C, Wang X, Zeng X, Dai Y. Characterization, High-Density Fermentation, and the Production of a Directed Vat Set Starter of Lactobacilli Used in the Food Industry: A Review. Foods 2022; 11:3063. [PMID: 36230139 PMCID: PMC9563398 DOI: 10.3390/foods11193063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/15/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Lactobacilli have been widely concerned for decades. Bacteria of the genus Lactobacillus have been commonly employed in fermented food to improve the appearance, smell, and taste of food or prolong its shelf-life. They comprise 261 species (by March 2020) that are highly diverse at the phenotypic, ecological, and genotypic levels. Some Lactobacilli strains have been documented to be essential probiotics, which are defined as a group of living microorganisms that are beneficial to the health of the host when ingested in sufficiency. However, the characterization, high-density fermentation, and the production of a directed vat set (DVS) starter of Lactobacilli strains used in the food industry have not been systematically reported. This paper mainly focuses on reviewing Lactobacilli as functional starter cultures in the food industry, including different molecular techniques for identification at the species and strain levels, methods for evaluating Lactobacilli properties, enhancing their performance and improving the cell density of Lactobacilli, and the production techniques of DVS starter of Lactobacilli strains. Moreover, this review further discussed the existing problems and future development prospects of Lactobacilli in the food industry. The viability and stability of Lactobacilli in the food industry and gastrointestinal environment are critical challenges at the industrial scale. The new production equipment and technology of DVS starter of Lactobacilli strains will have the potential for large-scale application, for example, developing low-temperature spray drying, freezing granulation drying, and spray freeze-drying.
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Affiliation(s)
- Yun Lu
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- Department of Brewing Engineering, Moutai University, Renhuai 564507, China
| | - Shuqi Xing
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China
| | - Laping He
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China
| | - Cuiqin Li
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China
- School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China
| | - Xiao Wang
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China
| | - Xuefeng Zeng
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China
| | - Yifeng Dai
- Key Laboratory of Agricultural and Animal Products Storage & Processing of Guizhou Province, Guizhou University, Guiyang 550025, China
- College of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China
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Selection of Lactiplantibacillus Strains for the Production of Fermented Table Olives. Microorganisms 2022; 10:microorganisms10030625. [PMID: 35336200 PMCID: PMC8956003 DOI: 10.3390/microorganisms10030625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 12/07/2022] Open
Abstract
Lactiplantibacillus strains (n. 77) were screened for technological properties (e.g., xylose fermentation, EPS production, antimicrobial activity, tolerance to NaCl and phenolic compounds, oleuropein degradation and hydroxytyrosol formation) relevant for the production of fermented table olives. Survival to olive mill wastewater (OMW) and to simulated gastro-intestinal tract (GIT), the capability to grow at different combinations of NaCl and pH values, radical scavenging activities and biofilm formation were further investigated in 15 selected strains. The screening step revealed high diversity among Lactiplantibacillus strains. Most of the strains were able to ferment xylose, while only a few strains produced EPS and had inhibitory activity against Y. lipolytica. Resistance to phenolic compounds (gallic, protocatechuic, hydroxybenzoic and syringic acids), as well as the ability to release hydroxytyrosol from oleuropein, was strain-specific. OMWs impaired the survival of selected strains, while combinations of NaCl ≤ 6% and pH ≥ 4.0 were well tolerated. DPPH and hydroxyl radical degradation were strain-dependent, while the capability to form biofilm was affected by incubation time. Strains were very tolerant to the GIT. The genome of Lpb. pentosus O17 was sequenced and analysed to verify the presence of genes involved in the degradation and metabolism of phenolic compounds. O17 lacks carboxylesterase and gallate decarboxylase (subunits B and D) sequences, and its gene profile differs from that of other publicly available Lpb. pentosus genomes.
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