Airborne Chloride Intensity and Chloride Ion Penetration into Mortar Specimen in Thailand

The Southern and Eastern parts of Thailand have long coastlines and are located in a hot and humid climate zone. A concrete structure in such environmental conditions tends to deteriorate owing to the corrosion of the steel reinforcement by airborne chloride. The concentration of airborne chloride varies by location and exposure conditions in each country. Thus, when designing concrete structures in such environments, the amount of airborne chloride and the concrete mix proportions should be carefully considered. However, the study of airborne chloride intensity and penetration in Thailand is still limited. This study examined the airborne chloride in the atmosphere in Phuket, Phang-Nga, and Chonburi Province. The amount of airborne chloride was checked every 1–3 months during the test period. Although the distances from the seashore are almost the same in all three locations, the airborne chloride intensity varied owing to the different exposure directions and environmental conditions. Additionally, analysis of mortar specimens with different sources of fly ash installed in Chonburi province to assess the airborne chloride penetration behavior showed that airborne chloride concentration varied with the breaking wave height, rainfall, and varied penetration rate based on the source of fly ash

Yeast diversity associated with the phylloplane of corn plants cultivated in Thailand

RTA5480009 RTA6080004 PHD/0025/2556The ecology and diversity of phylloplane yeasts is less well understood in tropical regions than in temperate ones. Therefore, we investigated the yeast diversity associated with the phylloplane of corn, an economically important crop in Thailand, by a culture-dependent method. Thirty-six leaf samples were collected and 217 yeast strains were isolated by plating leaf-washings. The strains were grouped by PCR-fingerprinting and representative strains were identified by analysis of the D1/D2 domain of the large subunit rRNA gene. In total, 212 strains were identified within 10 species in the Ascomycota and 32 species in the Basidiomycota. Five strains represented potential new species in the Basidiomycota, one strain was recently described as Papiliotrema plantarum, and four strains belonged to the genera Vishniacozyma and Rhodotorula. A higher number of strains in the Basidiomycota (81.6%) was obtained. Hannaella sinensis was the species with the highest occurrence. Principal coordinates analysis ordinations of yeast communities revealed that there were no differences in the similarity of the sampling sites. The estimation of the expected species richness showed that the observed species richness was lower than expected. This work indicated that a majority of yeast associated with the phylloplane of corn plant belongs to the phylum Basidiomycota.publishersversionpublishe

A Kluyveromyces marxianus 2-deoxyglucose-resistant mutant with enhanced activity of xylose utilization

Thermotolerant ethanologenic yeast Kluyveromyces marxianus is capable of fermenting various sugars including xylose but glucose represses to hamper the utilization of other sugars. To acquire glucose repression-defective strains, 33 isolates as 2-deoxyglucose (2-DOG)-resistant mutants were acquired from about 100 colonies grown on plates containing 2-DOG, which were derived from an efficient strain DMKU 3-1042. According to the characteristics of sugar consumption abilities and cell growth and ethanol accumulation along with cultivation time, they were classified into three groups. The first group (3 isolates) utilized glucose and xylose in similar patterns along with cultivation to those of the parental strain, presumably due to reduction of the uptake of 2-DOG or enhancement of its export. The second group (29 isolates) showed greatly delayed utilization of glucose, presumably by reduction of the uptake or initial catabolism of glucose. The last group, only one isolate, showed enhanced utilization ability of xylose in the presence of glucose. Further analysis revealed that the isolate had a single nucleotide mutation to cause amino acid substitution (G270S) in RAG5 encoding hexokinase and exhibited very low activity of the enzyme. The possible mechanism of defectiveness of glucose repression in the mutant is discussed in this paper. [Int Microbiol 18(4):235-244 (2015)]Keywords: Kluyveromyces marxianus · glucose repression · 2-deoxyglucose-resistant mutants · ethanol fermentation on xylose · thermotolerant yeas

Utilization capability of sucrose, raffinose and inulin and its less-sensitiveness to glucose repression in thermotolerant yeast Kluyveromyces marxianus DMKU 3-1042

Kluyveromyces marxianus possesses a useful potential to assimilate a wide variety of substrates at a high temperature, but the negative effect by coexisting glucose is critical for utilization of biomass containing various sugars. Such a negative effect on the activity of inulinase, which is the sole enzyme to hydrolyze sucrose, raffinose and inulin, has been demonstrated in K. marxianus without analysis at the gene level. To clarify the utilization capability of sucrose, raffinose and inulin and the glucose effect on inulinase in K. marxianus DMKU 3-1042, its growth and metabolite profiles on these sugars were examined with or without glucose under a static condition, in which glucose repression evidently occurs. Consumption of sucrose was not influenced by glucose or 2-deoxyglucose. On the other hand, raffinose and inulin consumption was hampered by glucose at 30°C but hardly hampered at 45°C. Unlike Saccharomyces cerevisiae, increase in glucose concentration had no effect on sucrose utilization. These sugar-specific glucose effects were consistent with the level of inulinase activity but not with that of the KmINU1 transcript, which was repressed in the presence of glucose via KmMig1p. This inconsistency may be due to sufficient activity of inulinase even when glucose is present. Our results encourage us to apply K. marxianus DMKU 3-1042 to high-temperature ethanol fermentation with biomass containing these sugars with glucose

Potential of Thermotolerant Ethanologenic Yeasts Isolated from ASEAN Countries and Their Application in High- Temperature Fermentation

Thermotolerant ethanologenic yeasts receive attention as alternative bio-ethanol producers to traditionally used yeast, Saccharomyces cerevisiae. Their utilization is expected to provide several benefits for bio-ethanol production due to their characteristics and robustness. They have been isolated from a wide variety of environments in a number of ASEAN countries: Thailand, Vietnam, Laos, and Indonesia. One of these yeasts, Kluyveromyces marxianus has been investigated regarding characteristics. Some strains efficiently utilize xylose, which is a main component of the 2nd generation biomass. In addition, the genetic basis of K. marxianus has been revealed by genomic sequencing and is exploited for further improvement of the strains by thermal adaptation or gene engineering techniques. Moreover, the glucose repression of K. marxianus and its mechanisms has been investigated. Results suggest that K. marxianus is an alternative to S. cerevisiae in next-generation bio-ethanol production industry. Indeed, we have succeeded to apply K. marxianus for bio-ethanol production in a newly developed process, which combines high-temperature fermentation with simultaneous fermentation and distillation under low pressure. This chapter aims to provide valuable information on thermotolerant ethanologenic yeasts and their application, which may direct the economic bioproduction of ethanol and other useful materials in the future

Tracking alternative versions of the galactose gene network in the genus Saccharomyces and their expansion after domestication

406564/2022-1 , and CNPq process numbers 0457499/2014-1 , 313088/2020-9 , and 408733/2021 , and Fundação do Amparo a Pesquisa do Estado de Minas Gerais ( FAPEMIG , process numbers APQ-01525-14 and APQ-02552-15 ). Field work in West Africa by L. Jespersen was supported by DANIDA , the Danish International Development Assistance. Publisher Copyright: © 2024 The AuthorsWhen Saccharomyces cerevisiae grows on mixtures of glucose and galactose, galactose utilization is repressed by glucose, and induction of the GAL gene network only occurs when glucose is exhausted. Contrary to reference GAL alleles, alternative alleles support faster growth on galactose, thus enabling distinct galactose utilization strategies maintained by balancing selection. Here, we report on new wild populations of Saccharomyces cerevisiae harboring alternative GAL versions and, for the first time, of Saccharomyces paradoxus alternative alleles. We also show that the non-functional GAL version found earlier in Saccharomyces kudriavzevii is phylogenetically related to the alternative versions, which constitutes a case of trans-specific maintenance of highly divergent alleles. Strains harboring the different GAL network variants show different levels of alleviation of glucose repression and growth proficiency on galactose. We propose that domestication involved specialization toward thriving in milk from a generalist ancestor partially adapted to galactose consumption in the plant niche.publishersversionpublishe

Marine yeast isolation and industrial application

Over the last century, terrestrial yeasts have been widely used in various industries, such as baking, brewing, wine, bioethanol and pharmaceutical protein production. However, only little attention has been given to marine yeasts. Recent research showed that marine yeasts have several unique and promising features over the terrestrial yeasts, for example higher osmosis tolerance, higher special chemical productivity and production of industrial enzymes. These indicate that marine yeasts have great potential to be applied in various industries. This review gathers the most recent techniques used for marine yeast isolation as well as the latest applications of marine yeast in bioethanol, pharmaceutical and enzyme production fields. Keyword

A genome-informed higher rank classification of the biotechnologically important fungal subphylum Saccharomycotina

Funding Information: We want to thank Barbara Roberts from the NCBI Taxonomy Team for providing the update of the current fungal names in NCBI Taxonomic database. Masako Takashima is supported by the Institution for Fermentation, Osaka (IFO). Heide-Marie Daniel is supported by the Belgian Science Policy Office grant C5/00/BCCM. Chris Todd Hittinger is supported by the National Science Foundation under Grant Nos. DEB-1442148 and DEB-2110403, the USDA National Institute of Food and Agriculture (Hatch Project 1020204), in part by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE–SC0018409, and an H.I. Romnes Faculty Fellowship, supported by the Office of the Vice Chancellor for Research and Graduate Education with funding from the Wisconsin Alumni Research Foundation. Research in Antonis Rokas’s lab is supported by grants from the National Science Foundation (DEB-1442113 and DEB-2110404), the National Institutes of Health/National Institute of Allergy and Infectious Diseases (R01 AI153356), and the Burroughs Wellcome Fund. Antonis Rokas acknowledges support from a Klaus Tschira Guest Professorship from the Heidelberg Institute for Theoretical Studies and from a Visiting Research Fellowship from Merton College of the University of Oxford. Marc-André Lachance acknowledges lifelong financial support from the Natural Sciences and Engineering Research Council of Canada. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Carlos A. Rosa is supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Brazil, process numbers 408733/2021-7 and 406564/2022-1); Fundação do Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG, process numberAPQ-01525-14). Teun Boekhout is supported by the Distinguished Scientist Fellow Program of King Saud University, Ryadh, Saudi Arabia. Publisher Copyright: © 2023 Westerdijk Fungal Biodiversity Institute.The subphylum Saccharomycotina is a lineage in the fungal phylum Ascomycota that exhibits levels of genomic diversity similar to those of plants and animals. The Saccharomycotina consist of more than 1 200 known species currently divided into 16 families, one order, and one class. Species in this subphylum are ecologically and metabolically diverse and include important opportunistic human pathogens, as well as species important in biotechnological applications. Many traits of biotechnological interest are found in closely related species and often restricted to single phylogenetic clades. However, the biotechnological potential of most yeast species remains unexplored. Although the subphylum Saccharomycotina has much higher rates of genome sequence evolution than its sister subphylum, Pezizomycotina, it contains only one class compared to the 16 classes in Pezizomycotina. The third subphylum of Ascomycota, the Taphrinomycotina, consists of six classes and has approximately 10 times fewer species than the Saccharomycotina. These data indicate that the current classification of all these yeasts into a single class and a single order is an underappreciation of their diversity. Our previous genome-scale phylogenetic analyses showed that the Saccharomycotina contains 12 major and robustly supported phylogenetic clades; seven of these are current families (Lipomycetaceae, Trigonopsidaceae, Alloascoideaceae, Pichiaceae, Phaffomycetaceae, Saccharomycodaceae, and Saccharomycetaceae), one comprises two current families (Dipodascaceae and Trichomonascaceae), one represents the genus Sporopachydermia, and three represent lineages that differ in their translation of the CUG codon (CUG-Ala, CUG-Ser1, and CUG-Ser2). Using these analyses in combination with relative evolutionary divergence and genome content analyses, we propose an updated classification for the Saccharomycotina, including seven classes and 12 orders that can be diagnosed by genome content. This updated classification is consistent with the high levels of genomic diversity within this subphylum and is necessary to make the higher rank classification of the Saccharomycotina more comparable to that of other fungi, as well as to communicate efficiently on lineages that are not yet formally named.publishersversionpublishe

Yeast Methylotrophy and Autophagy in a Methanol-Oscillating Environment on Growing Arabidopsis thaliana Leaves

The yeast Candida boidinii capable of growth on methanol proliferates and survives on the leaves of Arabidopsis thaliana. The local methanol concentration at the phyllosphere of growing A. thaliana exhibited daily periodicity, and yeast cells responded by altering both the expression of methanol-inducible genes and peroxisome proliferation. Even under these dynamically changing environmental conditions, yeast cells proliferated 3 to 4 times in 11 days. Among the C1-metabolic enzymes, enzymes in the methanol assimilation pathway, but not formaldehyde dissimilation or anti-oxidizing enzymes, were necessary for yeast proliferation at the phyllosphere. Furthermore, both peroxisome assembly and pexophagy, a selective autophagy pathway that degrades peroxisomes, were necessary for phyllospheric proliferation. Thus, the present study sheds light on the life cycle and physiology of yeast in the natural environment at both the molecular and cellular levels