Savitree Limtong

Kasetsart University | KU · Department of Microbiology

Seven strains of a novel Kluyveromyces species were isolated from seven water samples collected from a mangrove forest. Analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene sequences revealed that the sequences of five strains (RS8(T), RS20, RS54, RV42 and RV89) were identical and differed from the other two strains (RS65 and RV153) by...

Nine strains of a new Torulaspora species were isolated from natural samples collected in Japan and Thailand including one strain obtained from a leaf of Rhizophora stylosa (NBRC 11061T), one strain from soil (NBRC 11062), six strains from mosses (ST-14, ST-266, ST-510, ST-511, ST-513 and ST-581) and one strain from sediment in mangrove forest (RV-...

Two thermotolerant, methylotrophic yeast strains, PT44(T) and S051(T), were respectively isolated from a tree exudate and soil collected in Thailand. They were categorized as thermotolerant strains on the basis of their good growth below 20 degrees C and up to a relatively high temperature (37 degrees C). The major characteristics of the two strain...

Microbial lipids produced by oleaginous microorganisms, also called microbial oils and single cell oils (SCOs), are very promising sources for several oil industries. The exploration of efficient oleaginous yeast strains, meant to produce both high-quantity and high-quality lipids for the production of biodiesel, oleochemicals, and the other high v...

As an interesting alternative microbial platform for the sustainable synthesis of oleochemical building blocks and biofuels, oleaginous yeasts are increasing in both quantity and diversity. In this study, oleaginous yeast species from northern Thailand were discovered to add to the topology. A total of 127 yeast strains were isolated from 22 forest...

Seven yeast strains (UBIF12-1, UBFB13-1, SRFS56-3, SRFS57-2, SKFS62-1, SKFS66-1 and SKFS67-1) representing a single anamorphic novel yeast species were isolated from traditional Thai fermented foods in Ubon Ratchathani, Surin and Sisaket in the northeast part of Thailand. The results of analysis of the sequences of the D1/D2 region of the large sub...

Several cellulose-hydrolysis enzymes are required for eco-friendly utilization of cellulose as renewable biomass, and it would therefore be beneficial if fermenting microbes can provide such enzymes without genetic engineering. Thermotolerant and multisugar-fermenting Kluyveromyces marxianus is one of the promising yeasts for high-temperature ferme...

During ethanol fermentation, yeast cells are exposed to various stresses that have negative effects on cell growth, cell survival, and fermentation ability. This study, therefore, aims to develop Kluyveromyces marxianus-adapted strains that are multi-stress tolerant and to increase ethanol production at high temperatures through a novel evolutionar...

Three yeast strains, DMKU-MP6-4T, DMKU-MP2-6 and DMKU-MP5-1, were isolated from the small-intestinal content or Pia of cattle in Thailand during the investigation of yeast diversity in this habitat. According to the D1/D2 domain of the large subunit (LSU) rRNA gene and internal transcribed spacer (ITS) region sequence analysis, these strains repres...

The systematic position of 16 yeast strains isolated from Thailand, Hungary, The Netherlands, and the Republic of Poland were evaluated using morphological, physiological, and phylogenetic analyses. Based on the similarity of the D1/D2 domain of the LSU rRNA gene, the strains were assigned to two distinct species, Trichosporiella flavificans and re...

The intrinsic mechanism of the thermotolerance of Kluyveromyces marxianus was investigated by comparison of its physiological and metabolic properties at high and low temperatures. After glucose consumption, the conversion of ethanol to acetic acid became gradually prominent only at high temperature (45°C) and eventually caused a decline in viabili...

Strains SU22 T (TBRC 14875 T ) and FLA11.5, representing a novel anamorphic yeast species, were respectively isolated from a fruiting body of a Coprinus species and an inflorescence of a Coffea species collected in Thailand. Analysis of the sequences of the D1/D2 domains of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS)...

Seven yeast strains, representing a single novel anamorphic species, were isolated in Thailand. They consisted of five strains (DMKU-MRY16 T , DMKU-SK18, DMKU-SK25, DMKU-SK30 and DMKU-SK32) obtained from five different mushrooms, and two strains (ST-224 and 11-14.2) derived from insect frass and soil, respectively. The pairwise sequence analysis in...

Candida tropicalis, a xylose-fermenting yeast, has the potential for converting cellulosic biomass to ethanol. Thermotolerant C. tropicalis X-17, which was isolated in Laos, was subjected to repetitive long-term cultivation with a gradual increase in temperature (RLCGT) in the presence of a high concentration of glucose, which exposed cells to vari...

Citation: Phommachan, K.; Keo-oudone, C.; Nurcholis, M.; Vongvilaisak, N.; Chanhming, M.; Savanhnaly, V.; Bounphanmy, S.; Matsutani, M.; Kosaka, T.; Limtong, S.; et al. Adaptive Laboratory Evolution for Multistress Tolerance, including Fermentability at High Glucose Concentrations in Thermotolerant Candida tropicalis. Energies 2022, 15, 561. https:...

Ascomycetous yeast species in the genus Wickerhamomyces (Saccharomycetales, Wickerhamomycetaceae) are isolated from various habitats and distributed throughout the world. Prior to this study, 35 species had been validly published and accepted into this genus. Beneficially, Wickerhamomyces species have been used in a number of biotechnologically app...

Yeast diversity in the pia and small-intestinal epithelium of Pon Yang Kham fattening cattle in Thailand was studied using a culture-dependent method. A total of 701 yeasts were isolated from the pia of the duodenum, jejunum, and ileum of the small intestine, while 425 isolates were obtained from the epithelium of all three parts of the small intes...

Microbial lipids are considered to be potential raw materials for biodiesel production. However, the costs of such a process remain high due to the use of expensive feedstocks for microbial lipid production. The meat industry and biodiesel refineries generate amino acid (AA) wastes and crude glycerol, respectively, which could be explored as relati...

Indole-3-acetic acid (IAA) is the most common plant hormone of the auxin class and regulates various plant growth processes. The present study investigated IAA production by the basidiomycetous yeast Rhodosporidiobolus fluvialis DMKU-CP293 using the one-factor-at-a-time (OFAT) method and response surface methodology (RSM). IAA production was optimi...

Marine sponges harbor numerous microorganisms, among which sponge-associated yeasts are the least explored. To gain greater knowledge of sponge-associated yeasts, an investigation was therefore performed on marine sponges in Sattahip Bay, Gulf of Thailand, South China Sea. Seventy-one (71) marine sponge samples were collected at sites near Samae-sa...

Linoleic acid (LA) has garnered much attention due to its potential applications in the oleochemical and nutraceutical industries. The oleaginous yeast Rhodotorula toruloides has outstanding lipogenecity, and is considered a potential alternative to the current plant-based platforms for LA production. Δ12-fatty acid desaturases (Δ12-Fads) are invol...

As shown in our previous study, Kwoniella heveanensis DMKU-CE82, a volatile organic compound (VOC)-producing yeast, demonstrated promising antagonistic activity against aflatoxin-producing strain of Aspergillus flavus. This yeast’s volatile organic compounds (VOCs) could reduce Aflatoxin B1 (AFB1) in corn grains. In the current study, we evaluated...

Indole-3-acetic acid (IAA) is the most common plant hormone of the auxin class and regulates various plant growth processes. The present study investigated IAA production by the basidiomycetous yeast Rhodosporidiobolus fluvialis DMKU-CP293 using the one-factor-at-a-time (OFAT) method and response surface methodology (RSM). IAA production was optimi...

This study aimed to explore communities and the ethanol-fermenting ability of yeasts in fresh coconut, palmyra, and nipa palm saps. From the 90 samples of coconut, palmyra, and nipa palm saps, 204 yeast isolates were isolated and identified as 15 species in the phylum Ascomycota and a species (one strain) in Basidiomycota. Saccharomyces cerevisiae,...

Despite the abundance of yeasts in peatland, only a few studies on peatland yeasts have been reported and, further, most of those studies were carried out in boreal regions. In response, this study assesses yeast communities in tropical peat swamp forests (PSFs). Peat soils or soils from a primary or natural PSF were collected in Thailand at Khanth...

To enhance the microbial lipid production through Rhodosporidiobolus fluvialis DMKU-RK253, a two-stage cultivation process with a focus on cost reduction was developed. Low-cost raw materials, which are biodiesel-derived crude glycerol and monosodium glutamate were utilized to produce microbial lipids. A two-stage cultivation process was performed...

Stress tolerance is a desired characteristic of yeast strains for industrial applications. Stress tolerance has been well described in Saccharomyces yeasts but has not yet been characterized in oleaginous Rhodotorula yeasts even though they are considered promising platforms for lipid production owing to their outstanding lipogenicity. In a previou...

The strain DMKU-XD44, representing an anamorphic novel yeast species, was isolated from soil collected in a peat swamp forest (PSF) area in Rayong Botanical Garden in eastern Thailand. On the basis of sequence analysis of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region, Teunia cuniculi CBS 1030...

Seedling rot disease in rice leads to significant loss in the production of seedlings. This research was conducted to explore yeasts that could be used as biological control agents against rice seedling rot disease caused by Curvularia lunata and Helminthosporium oryzae. In total, 167 epiphytic yeast strains were evaluated, revealing that 13 of the...

Marine yeasts can occur in a wide range of habitats, including in marine invertebrates, in which they may play important roles; however, investigation of marine yeasts in marine invertebrates is scarce. Therefore, this study aims to explore the diversity of yeasts associated with corals and zoanthids in the Gulf of Thailand. Thirty-three coral and...

Lipids from oleaginous microorganisms, including oleaginous yeasts, are recognized as feedstock for biodiesel production. A production process development of these organisms is necessary to bring lipid feedstock production up to the industrial scale. This study aimed to enhance lipid production of low-cost substrates, namely sugarcane top and biodi...

Secondary peat swamp forest (PSF) arise by degradation of primary PSF as a result of fire and human activities. Yeasts diversity of Kuan Kreng (KK) and Rayong Botanical Garden (RBG) PSF, which are two secondary PSF in southern and in eastern Thailand, respectively, were investigated. Yeasts were isolated from soil and peat soil by the dilution plat...

Seven yeast strains, DMKU VGT1-14T, DMKU VGT1-19T, DMKU-JMGT1-28, DMKU-JMGT1-32, DMKU VGT2-06, DMKU VGT2-19 and DMKU VGT6-14, were isolated from a grease trap in Thailand and two strains, SJ-1 and SN-102 were isolated from the sea surface microlayer in Taiwan. On the basis of phenotypic characteristics and sequence analysis of the D1/D2 region of t...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The phylloplane is an important habitat for yeasts and these yeasts may have antagonistic activities against pathogens and could be used as biocontrol agents. To investigate rice phylloplane yeasts, 282 strains were isolated from 89 rice leaf samples and identified as 15 known yeast species in the phylum Ascomycota and 35 known and two potential ne...

To select antagonistic yeasts for the control of fruit rot caused by Lasiodiplodia theobromae and anthracnose caused by Colletotrichum gloeosporioides in postharvest mango fruit, 307 yeast strains isolated from plant leaves were evaluated for their antagonistic activities against these two fungal pathogens in vitro. Torulaspora indica DMKU-RP31, T....

In the original article, in the last sentence of the subsection 'Efficacy of VOC-producing yeasts on fungal conidial germination inhibition' in Materials and Methods, it should have read "3 = germ tube 2x to 4x" instead of "3 = germ tube 24x to 4x".

Aspergillus spp. are the most common phytopathogenic fungi able to produce various types of aflatoxins. Yeasts can produce volatile organic compounds (VOCs) that may be used as biocontrol agents against mycotoxigenic fungi. In this study, we aimed to evaluate antagonistic yeasts that are potentially capable of producing active VOCs against the afla...

Khanthuli peat swamp forest (PSF) is one of a few fertile peat swamp forests that remain in Thailand. It is composed of primary PSF and some areas which have been degraded to secondary PSF due to drought, wildfires and land conversion, which have resulted in a decrease in peat layers and change in the species of the plant community. In this study,...

This work aimed to evaluate in vitro antagonistic activities and mechanisms of endophytic yeasts against phytopathogenic fungi. A total of 407 yeast strains isolated from tissue of rice, corn, and sugarcane leaves were evaluated for their antagonistic activities against ten phytopathogenic fungi. Only strains of Wickerhamomyces anomalus and Kodamae...

Two strains (YSP-384 and YSP-399), representing a novel Torulaspora species, were isolated from two nipa inflorescence sap samples collected in Trang province in the southern part of Thailand. The two strains had identical sequences of the D1/D2 domains of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) regions. The two...

IAA biosynthetic pathways in a basidiomycetous yeast, Rhodosporidiobolus fluvialis DMKU-CP293, were investigated. The yeast strain showed tryptophan (Trp)-dependent IAA biosynthesis when grown in tryptophan supplemented mineral salt medium. Gas chromatography–mass spectrometry was used to further identify the pathway intermediates of Trp-dependent...

Kmmig1 as a disrupted mutant of MIG1 encoding a regulator for glucose repression in Kluyveromyces marxianus exhibits a histidine-auxotrophic phenotype. Genome-wide expression analysis revealed that only HIS4 in seven HIS genes for histidine biosynthesis was down-regulated in Kmmig1. Consistently, introduction of HIS4 into Kmmig1 suppressed the requ...

A thermotolerant ethanol fermenting yeast strain is a key requirement for effective ethanol production at high temperature. This work aimed to select a thermotolerant yeast producing a high ethanol concentration from molasses and increasing its ethanol production by mutagenesis. Saccharomyces cerevisiae DMKU 3-S087 was selected from 168 ethanol pro...

Kmmig1 as a disrupted mutant of MIG1 encoding a regulator for glucose repression in Kluyveromyces marxianus exhibits a histidine-auxotrophic phenotype. Genome-wide expression analysis revealed that only HIS4 in seven HIS genes for histidine biosynthesis was down-regulated in Kmmig1. Consistently, introduction of HIS4 into Kmmig1 suppressed the requ...

Three strains, representing a novel anamorphic and d-xylose-fermenting yeast species, were isolated from moss (ST-302T), seawater (ST-1169) and peat (DMKU-XE12) collected from the southern part of Thailand. The three strains had identical sequences of the D1/D2 regions of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) r...

Ten strains representing a single anamorphic novel yeast species were isolated from the external surface (DMKU-SP23 and DMKU-SP40) and tissue (DMKU-SE89, DMKU-SE99, DMKU-SE100 and DMKU-SE147) of sugarcane leaves in Thailand, and phylloplane (IMUFRJR 52034) and rhizoplane (IMUFRJ 52036 and 52037) of sugarcane and associated soil (IMUFRJ 52035) in Br...

The study aimed to investigate yeast communities in sugarcane (Saccharum officinarum Linn.) phylloplane in Thailand by a culture-dependent approach using a direct isolation method; namely, plating of leaf washing for yeast isolation. A total of 150 yeast strains were obtained from 79 sugarcane leaf samples collected in ten provinces. Identification...

This study aimed to investigate an inexpensive enrichment medium for obtaining acid-resistant purple nonsulfur bacteria (PNSB) from peat swamp forests (PSF), screening PNSB for their biofertilizer and biocontrol properties, and investigating physico-chemical properties of PSF. Rice straw and G5 broths were used to count PNSB in PSF of Southern Thai...

To analyze the glucose repression mechanism in the thermotolerant yeast Kluyveromyces marxianus, disrupted mutants of genes for Mig1 and Rag5 as orthologs of Mig1 and Hxk2, respectively, in Saccharomyces cerevisiae were constructed, and their characteristics were compared with those of the corresponding mutants of S. cerevisiae. MIG1 mutants of bot...

To analyze the glucose repression mechanism in the thermotolerant yeast Kluyveromyces marxianus, disrupted mutants of genes for Mig1 and Rag5 as orthologs of Mig1 and Hxk2, respectively, in Saccharomyces cerevisiae were constructed, and their characteristics were compared with those of the corresponding mutants of S. cerevisiae. MIG1 mutants of bot...

Objectives 1. To isolate and characterize 2-deoxyglucose (2-DOG)-resistant mutants either spontaneously or by insertion of kanMX4 DNA fragment in thermotolerant yeast Kluyveromyces marxianus DMKU 3-1042. 2. To understand the regulation of glucose repression mechanism in K. marxianus DMKU 3-1042.

Strain DMKU-SP105T representing a novel yeast species was isolated from the external surface of a sugarcane leaf (Saccharum officinarum L.) collected from a sugarcane plantation field in Phichit province, Thailand. On the basis of sequence analysis of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) re...

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...

The oil plants provide a sufficient source of renewable lipid production for alternative fuel and chemical supplies as an alternative to the depleting fossil source, but the environmental effect from these plants’ cropping is a concern. The high oleic acid (OA; C18:1) content in plant-derived products provide advantages of multiple uses with improv...

Strain DMKU13-2T, representing a novel anamorphic yeast species in the class Microbotryomycetes, subphylum Puccinomycotina, phylum Basidiomycota, was isolated from a soft coral collected in the sea off Ko Mu island, Thailand. The phylogenetic analysis based on the concatenated sequences of the internal transcribed spacer (ITS) region and the D1/D2...

Oleaginous yeast Rhodosporidium toruloides DMKU3-TK16 (TK16), which was isolated from Thailand, is considered a promising lipid producer for biodiesel production. For future industrial applications of this strain, thermotolerant traits are highly desired for their potential to reduce cooling costs in a commercial fermenter. Here, by using an adapti...

Two strains, which formed pink colonies and produced ballistoconidia and represented a novel anamorphic yeast species, were isolated from peat (DMKU-SPS1-2) and fern leaf (ST-145) collected in Thailand. Analysis of the sequences of the D1/D2 domains of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) regions showed that t...

Three strains (DMKU-XE11T, DMKU-XE15 and DMKU-XE20) representing a single novel anamorphic and d-xylose-fermenting yeast species were obtained from three peat samples collected from Khan Thulee peat swamp forest in Surat Thani province, Thailand. The strains differed from each other by one to two nucleotide substitutions in the sequences of the D1/...

During a survey of the yeast community associated with the phylloplane of corn in Thailand, a basidiomycetous yeast strain belonging to the genus Papiliotrema was isolated. Analyses of the D1/D2 domains of the 26S (LSU) rRNA gene and complete ITS region supported the recognition of a novel species, for which the name Papiliotrema plantarum sp. nov....

Endophytic yeasts are yeast that can colonize healthy plant tissues without causing any damage to the host plant. This work aimed to explore the diversity of endophytic yeasts in leaf tissue of main agricultural crops (rice, corn and sugarcane) in Thailand, by a culture-dependent approach. A total of 311 leaf samples, consisting of rice (n = 100),...

Two strains (DMKU-PPS4-5Tand DMKU-EPS3-4) representing a single novel anamorphic yeast species were isolated from two peat samples collected in Kan Tulee peat swamp forest, Surat Thani Province, Thailand. The strains differed by two nucleotide substitutions in the sequences of the D1/D2 region of the large subunit (LSU) rRNA gene and only one nucle...

Grasshoppers play vital role in the digestion of photosynthetically fixed carbons. With the aid of intestinal microflora, the grasshopper can degrade leaves constituents such as cellulose and hemicellulose. The purpose of this study was to examine cellulolytic yeast isolates from the gut of grasshoppers collected in Gyeonggi Province, South Korea....

Lipid was produced by Rhodosporidiobolus fluvialis DMKU-SP314 from a mixture of low-cost substrates: sugarcane top hydrolysate (STH) and biodiesel-derived crude glycerol. The optimized lipid production medium for shaking flask cultivation contained STH supplemented with 59g/L crude glycerol, 0.21g/L soybean powder, 0.9g/L (NH4)2SO4, 0.4g/L KH2PO4,...

Triacylglycerol (TAG) is a major component of lipid storage in yeast. The acyl CoA: diacylgycerol acyltransferase (DGAT) that catalyzes the final and rate-limiting step in the production of TAG is rather interesting. Consequently, cloning and analysis of the gene-encoding TAG synthase, diacylglycerol acyltransferase gene (DGA1), of the oleaginous y...

Phylloplane, which refers to the surfaces of aboveground parts of plants, includes mainly leaves and has been recognized as an important habitat for microorganisms. The growth of phylloplane microorganisms is dependent on organic and inorganic substances on the leaf surfaces that are either secreted by the plant or originate from external sources....