Applied Microbiology and Biotechnology最新文献

{"title":"Characterization of a novel D-sorbitol dehydrogenase from Faunimonas pinastri A52C2","authors":"Shuangshuang Yu,&nbsp;Youran Li,&nbsp;Guiyang Shi,&nbsp;Sha Xu,&nbsp;Liang Zhang,&nbsp;Zhongyang Ding","doi":"10.1007/s00253-024-13381-2","DOIUrl":"10.1007/s00253-024-13381-2","url":null,"abstract":"<p>The enzyme D-sorbitol dehydrogenase (SLDH) facilitates the conversion of D-sorbitol to L-sorbose. While current knowledge of this enzyme class predominantly centers on <i>Gluconobacter oxydans</i>, the catalytic properties of enzymes from alternative sources, particularly their substrate specificity and coenzyme dependency, remain ambiguous. In this investigation, we conducted BLASTp analysis and screened out a novel SLDH (Fpsldh) from <i>Faunimonas pinastri</i> A52C2. The SLDH was then identified and characterized. Analysis of the purified enzyme revealed its dependence on NAD⁺/NADP⁺ and its specificity for L-sorbose production. Fpsldh demonstrated sustained catalytic activity over temperatures ranging from 27 to 37 ℃, with optimal performance observed at pH 8.0–10.0, and it exhibited no requirement for metal ions for activation. The <i>K</i>_<i>m</i> of Fpsldh is 7.51 mM. Furthermore, a <i>Bacillus licheniformis</i> host expressing Fpsldh was engineered. The resultant whole-cell catalyst yielded 13.19 g/L of L-sorbose after 33.6 h of transformation, obviating the need for exogenous cofactors. This study enhances our understanding of the catalytic properties of the SLDH family and introduces a novel method for L-sorbose production, a compound of considerable commercial value.</p><p><i>•New D-sorbitol dehydrogenase from Faunimonas pinastri A52C2 is characterized.</i></p><p><i>•Fpsldh is not PQQ but NAD</i>^<i>+</i><i>/NADP</i>^<i>+</i><i>-dependent.</i></p><p><i>•Bacillus licheniformis expressing Fpsldh can produce 13.19 g/L L-sorbose within 33.6 h.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11772468/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143045454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering yeast to produce fraxetin from ferulic acid and lignin","authors":"Bo-Tao He,&nbsp;Bing-Zhi Li","doi":"10.1007/s00253-025-13409-1","DOIUrl":"10.1007/s00253-025-13409-1","url":null,"abstract":"<p>Lignin, the most abundant renewable source of aromatic compounds on earth, remains underexploited in traditional biorefining. Fraxetin, a naturally occurring flavonoid, has garnered considerable attention in the scientific community due to its diverse and potent biological activities such as antimicrobial, anticancer, antioxidant, anti-inflammatory, and neurological protective actions. To enhance the green and value-added utilization of lignin, <i>Saccharomyces cerevisiae</i> was engineered as a cell factory to transform lignin derivatives to produce fraxetin. The expression of scopoletin 8-hydroxylase (S8H) and coumarin synthase (COSY) enabled <i>S. cerevisiae</i> to produce fraxetin from ferulic acid, one of the three principal monomers. The optimized fermentation strategies produced 19.1 mg/L fraxetin from ferulic acid by engineered <i>S. cerevisiae</i>. Additionally, the engineered cell factory achieved a fraxetin titer of 7.7 mg/L in lignin hydrolysate. This study successfully demonstrates the biotransformation of lignin monomers and lignin hydrolysate into fraxetin using a <i>S. cerevisiae</i> cell factory, thereby providing a viable strategy for the valorization of lignin.</p><p><i>• AtS8H showed substance specificity in the hydroxylation of scopoletin.</i></p><p><i>• AtCOSY and AtS8H were key enzymes for converting ferulic acid into fraxetin.</i></p><p><i>• Yeast was engineered to produce fraxetin from lignin hydrolysate.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11772470/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143057402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The activity of indigo carmine against bacteriophages: an edible antiphage agent","authors":"Sada Raza,&nbsp;Bartłomiej Bończak,&nbsp;Nataliia Atamas,&nbsp;Aneta Karpińska,&nbsp;Tomasz Ratajczyk,&nbsp;Marcin Łoś,&nbsp;Robert Hołyst,&nbsp;Jan Paczesny","doi":"10.1007/s00253-025-13414-4","DOIUrl":"10.1007/s00253-025-13414-4","url":null,"abstract":"<p>Bacteriophage infections in bacterial cultures pose a significant challenge to industrial bioprocesses, necessitating the development of innovative antiphage solutions. This study explores the antiphage potential of indigo carmine (IC), a common FDA-approved food additive. IC demonstrated selective inactivation of DNA phages (P001, T4, T1, T7, λ) with the EC₅₀ values ranging from 0.105 to 0.006 mg/mL while showing no activity against the RNA phage MS2. Fluorescence correlation spectroscopy (FCS) revealed that IC selectively binds to dsDNA, demonstrated by a significant reduction in the diffusion coefficient, whereas no binding was observed with ssDNA or RNA. Mechanistically, IC permeates the phage capsid, leading to genome ejection and capsid deformation, as confirmed by TEM imaging. Under optimal conditions (50 °C, 220 rpm), IC achieved up to a 7-log reduction in phage titer, with kinetic theory supporting the enhanced collision frequency induced by agitation. Additionally, IC protected <i>E. coli</i> cultures from phage-induced lysis without affecting bacterial growth or protein production, as demonstrated by GFP expression assays. IC’s effectiveness and environmental safety, combined with its FDA approval and cost-effectiveness, make it a promising antiphage agent for industrial applications.</p><p>• <i>Indigo </i><i>carmine effectively inactivates a broad spectrum of bacteriophages, offering protection to bacteria in industrial cultures.</i></p><p>• <i>A novel application of indigo carmine as a food-grade, environmentally safe, and FDA-approved antiphage agent protecting bacterial cultures.</i></p><p>• <i>Antiphage activity arises from indigo carmine’s interaction with DNA within the phage capsid without harming bacterial cells or compromising protein production in bacterial cultures.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11762416/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure and assembly mechanisms of the microbial community on an artificial reef surface, Fangchenggang, China","authors":"Jian Zou,&nbsp;Yu Guo,&nbsp;Ankai Zhang,&nbsp;Guangyu Shao,&nbsp;Zhenhua Ma,&nbsp;Gang Yu,&nbsp;Chuanxin Qin","doi":"10.1007/s00253-025-13415-3","DOIUrl":"10.1007/s00253-025-13415-3","url":null,"abstract":"<p>The construction of artificial reefs (ARs) is an effective way to restore habitats and increase and breed fishery resources in marine ranches. However, studies on the impacts of ARs on the structure, function, and assembly patterns of the bacterial community (BC), which is important in biogeochemical cycles, are lacking. The compositions, diversities, assembly patterns, predicted functions, and key environmental factors of the attached and free-living microbial communities in five-year ARs (O-ARs) and one-year ARs (N-ARs) in Fangchenggang, China, were analyzed via 16S rRNA gene sequencing. <i>Proteobacteria</i> was the dominant taxon in all the samples, with an average relative abundance of 44.48%, followed by <i>Bacteroidetes</i> (17.42%) and <i>Cyanobacteria</i> (15.19%). The composition of bacterial phyla was similar between O-ARs and N-ARs, but the relative abundance of <i>Cyanobacteria</i> was greater in the water column (38.56%) than on the AR surface (mean of 7.40%). The results revealed that the Shannon‒Wiener diversity indices were 5.64 and 5.45 for O-ARs and N-ARs, respectively. Principal coordinate analysis (PCoA) revealed different distributions of O-ARs and N-ARs in the microbial community. Additionally, network analysis revealed that the bacterial community was more complex and stable in O-ARs than in N-ARs, indicating that the 5-year AR presented a more diverse and stable microbial community overall. The KEGG database was used to predict that nitrogen metabolism, carbon metabolism, and membrane transport were the dominant microbial functions, accounting for 29.93% of the total functional abundances. The results of the neutral community model revealed that stochastic processes (67.2%) dominated the assembly of BCs. Interestingly, deterministic processes may be increasingly important in community aggregation over time. Moreover, a null model revealed that dispersal limitation was the most important process among the stochastic processes, accounting for 57.14% of the total. In addition, redundancy analysis (RDA) revealed that hydrological factors obviously impacted the structure and function of the microbial community. Our results showed that the construction of ARs slightly promotes local diversities in the structure and function of the microbial community, indicating it requires a longer time to enhance the diversity of the microbial community on artificial reefs.</p><p>• <i>Artificial reefs facilitate the diversity and functions of the microbial community</i></p><p>• <i>Stochastic processes dominate the assembly of the microbial community in artificial reefs</i></p><p>• <i>Nitrogen and carbon metabolism dominate microbial functions in artificial reefs</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11762584/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143036281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationship assessment of microbial community and cometabolic consumption of 2-chlorophenol","authors":"Miguel Martínez-Jardines,&nbsp;Omar Oltehua-López,&nbsp;Sergio Martínez-Hernández,&nbsp;Anne-Claire Texier,&nbsp;Flor de María Cuervo-López","doi":"10.1007/s00253-025-13403-7","DOIUrl":"10.1007/s00253-025-13403-7","url":null,"abstract":"<p>The relationship of microbial community and cometabolic consumption of 2-chlorophenol (2-CP) in a nitrifying sequencing batch reactor (SBR) was studied. The assessment of the population dynamics of the nitrifying sludge during the cometabolic 2-CP consumption with increasing ammonium (NH₄⁺) concentrations in the SBR showed the presence of 39 different species of which 10 were always present in all cycles. Fifty-five percent of the species found were grouped as Proteobacteria (45% as β-proteobacteria and 10% as γ-proteobacteria class), 30% as Acidobacteria, and 15% as Deinococcus-Thermus phyla. NH₄⁺ and cometabolic 2-CP consumption could be related to the presence and permanence of ammonium-oxidizing bacteria (AOB) species and heterotrophic bacteria, while the complete nitrification to the presence of nitrite-oxidizing bacteria (NOB) species. A correlation analysis showed that the complete and stable nitrifying performance (NH₄⁺ consumption efficiencies (ENH₄⁺-N) &gt; 99% and nitrate production yields (YNO₃⁻-N) between 0.93 and 0.99), as well as the increase in specific rates (ammonium (qNH₄⁺-N) and 2-CP (q2-CP-C) consumption and nitrate production (qNO₃⁻-N)), was associated with the homogeneity of the bacterial community (<i>J</i> index = 0.99). The increase in the proportion of individuals of AOB species such as <i>Nitrosomonas oligotropha</i> and <i>Nitrosomonas marina</i> was associated with the increase in qNH₄⁺-N (<i>r</i> ≥ 0.69) and q2-CP-C (<i>r</i> ≥ 0.64) and, therefore, with the 2-CP cometabolic consumption in the SBR. Finally, the increase in the proportion of individuals of heterotrophic species such as <i>Dokdonella ginsengisoli</i>, <i>Deinococcus peraridilitoris</i>, <i>Truepera radiovictrix</i>, and <i>Stenotrophobacter terrae</i> was associated with the increase in q2-CP-C (<i>r</i> ≥ 0.59).</p><p>• <i>Thirty-nine bacterial species were identified in the nitrifying sludge population of the SBR.</i></p><p>• <i>β-Proteobacteria and Acidobacteria were the prevalent (85%) bacterial groups.</i></p><p>• <i>AOB and heterotrophic bacteria participate in NH</i>_<i>4</i>^<i>+</i><i> and cometabolic 2-CP consumption.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11761499/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aloin remodels the cell wall of Candida albicans to reduce its hyphal virulence against oral candidiasis","authors":"Binyou Liao,&nbsp;Chuanli Zhang,&nbsp;Jiawei Shen,&nbsp;Ding Chen,&nbsp;Jiannan Wang,&nbsp;Xi Chen,&nbsp;Yuan Zhou,&nbsp;Yu Wei,&nbsp;Yangyang Shi,&nbsp;Lichen Gou,&nbsp;Qiang Guo,&nbsp;Xinxuan Zhou,&nbsp;Hongyu Xie,&nbsp;Lin Zhao,&nbsp;Ga Liao,&nbsp;Zhuoli Zhu,&nbsp;Lei Cheng,&nbsp;Xuedong Zhou,&nbsp;Yan Li,&nbsp;Biao Ren","doi":"10.1007/s00253-025-13411-7","DOIUrl":"10.1007/s00253-025-13411-7","url":null,"abstract":"<p><i>Aloe vera</i> (L.) Burm.f. is a traditional Chinese medicine known for treating various ailments, including fungal infections. Aloin is one of the major components from <i>A. vera</i>, but its antifungal mechanism and therapeutic potential against oral candidiasis are not clear. This study aimed to examine the mechanism of aloin against <i>Candida albicans</i> and its inhibitory activity against oral candidiasis. In this study, we for the first time found that aloin could induce the formation of abnormal hyphae with smaller hyphal diameters and fewer branching points in <i>C. albicans</i> including 11 clinical isolates without growth inhibition. The transcriptome and further cell wall contents analysis indicated that aloin remodeled the cell wall to increase the contents of β-1,3-glucan and furtherly showed an antagonistic effect with micafungin. Aloin also significantly inhibited the cell damage of oral epithelial cells and oral candidiasis in mice infected by <i>C. albicans</i> due to its inhibitory actions on the hyphal development and expressions of virulence factors, including candidalysin (coded by <i>ECE1</i>). Our results suggest that aloin is a promising antifungal agent for controlling candidiasis and targeting hyphal development and pathogenesis represents a practical strategy for developing new antifungal drugs.</p><p>• <i>Aloin remodels the C. albicans cell wall to form avirulent hyphae.</i></p><p>• <i>Aloin inhibits C. albicans infections in oral epithelial cells and mouse mucosa without toxicity.</i></p><p>• <i>Aloin is a promising antifungal agent with therapeutic potential against C. albicans infections.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11761986/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of ribosomal protein S1 mutants for improving of expression of difficult to translate mRNAs","authors":"Laura R. K. Niemelä,&nbsp;András Pásztor,&nbsp;Alexander D. Frey","doi":"10.1007/s00253-025-13406-4","DOIUrl":"10.1007/s00253-025-13406-4","url":null,"abstract":"<p>Metagenomes present a source for novel enzymes, but under 1% of environmental microbes are cultivatable. Because of its useful properties, <i>Escherichia coli</i> has been used as a host organism in functional genomic screens. However, due to differing expression machineries in the expression host compared to the source organism of the DNA sequences, screening outcomes can be biased. Here, we focused on one of the limiting processes—translation initiation. To that end, we created an operon-like screening system in <i>E. coli</i> to select mutants of the ribosomal protein S1 with more relaxed sequence requirements for 5’-untranslated regions of mRNAs. We created two mutation libraries of the ribosomal protein S1, one covering domains 3 and 4 (D3-D4) and the second covering domains 3 to 5 (D3-D5). Most mutants from library D3-D4 proofed to be specific for a particular UTR sequence and improved only expression from a single construct. Only mutant 3 from library D3-D4 led to increased expression of four different reporters improving fluorescence levels by up to 21%. Mutants isolated from D3-D5 library led up to 90% higher expression compared to the control, though the mutants with highest improvements exhibited a specialist phenotype. The most promising mutant, mutant 4, exhibited a generalist phenotype and showed increased expression in all six reporter strains compared to the control. This could indicate the potential for a more promiscuous translation initiation of metagenomic sequences in <i>E. coli</i> although at the price of smaller increases compared to specialist mutants.</p><p><i>• An operon-like selection system allowed to isolate generalist and specialist S1 mutants.</i></p><p><i>• S1 mutants improved translation of mRNAs with 5'-UTRs from metagenomic sequences.</i></p><p><i>• Use of S1 mutants could increase coverage from metagenomic libraries in functional screens.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11759276/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143021644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in fungal sugar transporters: unlocking the potential of second-generation bioethanol production","authors":"Lucas Matheus Soares Pereira,&nbsp;Iasmin Cartaxo Taveira,&nbsp;David Batista Maués,&nbsp;Renato Graciano de Paula,&nbsp;Roberto N. Silva","doi":"10.1007/s00253-025-13408-2","DOIUrl":"10.1007/s00253-025-13408-2","url":null,"abstract":"<p>Second-generation (2G) bioethanol production, derived from lignocellulosic biomass, has emerged as a sustainable alternative to fossil fuels by addressing growing energy demands and environmental concerns. Fungal sugar transporters (STs) play a critical role in this process, enabling the uptake of monosaccharides such as glucose and xylose, which are released during the enzymatic hydrolysis of biomass. This mini-review explores recent advances in the structural and functional characterization of STs in filamentous fungi and yeasts, highlighting their roles in processes such as cellulase induction, carbon catabolite repression, and sugar signaling pathways. The review also emphasizes the potential of genetic engineering to enhance the specificity and efficiency of these transporters, overcoming challenges such as substrate competition and limited pentose metabolism in industrial strains. By integrating the latest research findings, this work underscores the pivotal role of fungal STs in optimizing lignocellulosic bioethanol production and advancing the bioeconomy. Future prospects for engineering transport systems and their implications for industrial biotechnology are also discussed.</p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00253-025-13408-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of a novel butenolide signal system to regulate high production of tylosin in Streptomyces fradiae","authors":"Huliang Chen,&nbsp;Xiang Liu,&nbsp;Baoting Wei,&nbsp;Yuqing Tian,&nbsp;Yue Li,&nbsp;Jihui Zhang,&nbsp;Huarong Tan,&nbsp;Jine Li","doi":"10.1007/s00253-024-13396-9","DOIUrl":"10.1007/s00253-024-13396-9","url":null,"abstract":"<p>Identifying hormone-like quorum sensing (QS) molecules in streptomycetes is challenging due to low production levels but is essential for understanding secondary metabolite biosynthesis and morphological differentiation. This work reports the discovery of a novel γ-butenolide-type signaling molecule (SFB1) via overexpressing its biosynthetic gene (<i>orf18</i>) in <i>Streptomyces fradiae</i>. SFB1 was found to be essential for production of tylosin through dissociating the binding of its receptor TylP (a transcriptional repressor) to target genes, thus activating the expression of tylosin biosynthetic gene cluster (<i>tyl</i>). Meanwhile, SFB1 biosynthesis is negatively regulated by TylQ (another transcriptional repressor); the disruption of its coding gene <i>tylQ</i> led to increased production of SFB1, which in turn increased the yield of tylosin. Using <i>tylQ</i> disrupted mutant as chassis cell, co-overexpressing transcriptional activators TylR and TylS further increased tylosin yield to 3926 ± 110 mg/L, representing a 2.93-fold improvement over the wild-type strain. Since the quorum sensing signaling system can affect the biosynthesis of many secondary metabolites, thereby this strategy may also be readily applied for improving the titers of other microbial metabolites.</p><p>• <i>SFB1 is a novel γ-butenolide-type quorum sensing signaling molecule of S. fradiae</i>.</p><p>• <i>SFB1 regulates the production of tylosin</i>.</p><p>• <i>Engineering SFB1 regulatory cascade improves tylosin production</i>.</p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00253-024-13396-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation and characterization of haploid heterothallic beer yeasts","authors":"Jennifer Badura,&nbsp;Beatrice Bernardi,&nbsp;Judith Muno-Bender,&nbsp;Katrin Matti,&nbsp;Kerstin Zimmer,&nbsp;Jürgen Wendland","doi":"10.1007/s00253-024-13397-8","DOIUrl":"10.1007/s00253-024-13397-8","url":null,"abstract":"<p>Improving ale or lager yeasts by conventional breeding is a non-trivial task. Domestication of lager yeasts, which are hybrids between <i>Saccharomyces cerevisiae</i> and <i>Saccharomyces eubayanus</i>, has led to evolved strains with severely reduced or abolished sexual reproduction capabilities, due to, e.g. postzygotic barriers. On the other hand, <i>S. cerevisiae</i> ale yeasts, particularly Kveik ale yeast strains, were shown to produce abundant viable spores (~ 60%; Dippel et al. Microorganisms 10(10):1922, 2022). This led us to investigate the usefulness of Kveik yeasts for conventional yeast breeding. Surprisingly, we could isolate heterothallic colonies from germinated spores of different Kveik strains. These strains presented stable mating types in confrontation assays with pheromone-sensitive tester strains. Heterothallism was due to inactivating mutations in their <i>HO</i> genes. These led to amino acid exchanges in the Ho protein, revealing a known G223D mutation and also a novel G217R mutation, both of which abolished mating type switching. We generated stable <i>MAT</i><b><i>a</i></b> or <i>MATα </i>lines of four different Kveik yeasts, named Odin, Thor, Freya and Vör. Analyses of bud scar positions in these strains revealed both axial and bipolar budding patterns. However, the ability of Freya and Vör to form viable meiotic offspring with haploid tester strains demonstrated that these strains are haploid. Fermentation analyses indicated that all four yeast strains were able to ferment maltose and maltotriose. Odin was found to share not only mutations in the <i>HO</i> gene, but also inactivating mutations in the <i>PAD1</i> and <i>FDC1</i> genes with lager yeasts, which makes this strain POF-, i.e. not able to generate phenolic off-flavours, a key feature of lager yeasts. These haploid ale yeast-derived strains may open novel avenues also for generating novel lager yeast strains by breeding or mutation and selection utilizing the power of yeast genetics, thus lifting a block that domestication of lager yeasts has brought about.</p><p><i>• Haploid Kveik ale yeasts with stable MAT</i><b><i>a</i></b><i> and MATα mating types were isolated.</i></p><p><i>• Heterothallic strains bear mutant HO alleles leading to a novel inactivating G217R amino acid change.</i></p><p><i>• One strain was found to be POF- due to inactivating mutations in the PAD1 and FDC1 gene rendering it negative for phenolic off-flavor production.</i></p><p><i>• These strains are highly accessible for beer yeast improvements by conventional breeding, employing yeast genetics and mutation and selection regimes.</i></p>","PeriodicalId":8342,"journal":{"name":"Applied Microbiology and Biotechnology","volume":"109 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00253-024-13397-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}