scholarly journals Kluyveromyces marxianus: Current State of Omics Studies, Strain Improvement Strategy and Potential Industrial Implementation

Fermentation ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 124
Author(s):  
Dung Minh Ha-Tran ◽  
Trinh Thi My Nguyen ◽  
Chieh-Chen Huang

Bioethanol is considered an excellent alternative to fossil fuels, since it importantly contributes to the reduced consumption of crude oil, and to the alleviation of environmental pollution. Up to now, the baker yeast Saccharomyces cerevisiae is the most common eukaryotic microorganism used in ethanol production. The inability of S. cerevisiae to grow on pentoses, however, hinders its effective growth on plant biomass hydrolysates, which contain large amounts of C5 and C12 sugars. The industrial-scale bioprocessing requires high temperature bioreactors, diverse carbon sources, and the high titer production of volatile compounds. These criteria indicate that the search for alternative microbes possessing useful traits that meet the required standards of bioethanol production is necessary. Compared to other yeasts, Kluyveromyces marxianus has several advantages over others, e.g., it could grow on a broad spectrum of substrates (C5, C6 and C12 sugars); tolerate high temperature, toxins, and a wide range of pH values; and produce volatile short-chain ester. K. marxianus also shows a high ethanol production rate at high temperature and is a Crabtree-negative species. These attributes make K. marxianus promising as an industrial host for the biosynthesis of biofuels and other valuable chemicals.

Author(s):  
Dung Minh Ha-Tran ◽  
Trinh Thi My Nguyen ◽  
Chieh-Chen Huang

Bioethanol has been considered as an excellent alternative to fossil fuels since it importantly contributes to the reduced consumption of the crude oil and to the alleviation of environmental pollution [1]. Up to now, the baker yeast Saccharomyces cerevisiae is the most common eukaryotic microorganism used in ethanol production. The inability of S. cerevisiae to grow on pentoses, however, hinders its effective growth on plant biomass hydrolysates, which contain large amounts of C5 and C12 sugars. The industrial-scale bioprocessing requires high temperature bioreactors, diverse carbon sources, and the high titer production of volatile compounds [2]. These criteria indicate that the search for alternative microbes possessing useful traits that meet the required standards of bioethanol production is necessary. Compared to other yeasts, Kluyveromyces marxianus has several advantages over the others, e.g. it could grow on a broad spectrum of substrates (C5, C6 and C12 sugars) [3], tolerate to high temperature, toxin [4,5] and a wide range of pH values [6], and produce volatile short-chain ester [2]. K. marxianus also shows a high ethanol production rate at high temperature and is a Crabtree-negative species [7]. These attributes make K. marxianus a promise as an industrial host for the biosynthesis of biofuels and other valuable chemicals.


2017 ◽  
Author(s):  
Chenlu Zhang ◽  
Ligia Acosta-Sampson ◽  
Vivian Yaci Yu ◽  
Jamie H. D. Cate

AbstractThe economic production of cellulosic biofuel requires efficient and full utilization of all abundant carbohydrates naturally released from plant biomass by enzyme cocktails. Recently, we reconstituted the Neurospora crassa xylodextrin transport and consumption system in Saccharomyces cerevisiae, enabling growth of yeast on xylodextrins aerobically. However, the consumption rate of xylodextrin requires improvement for industrial applications, including consumption in anaerobic conditions. As a first step in this improvement, we report analysis of orthologues of the N. crassa transporters CDT-1 and CDT-2. Transporter ST16 from Trichoderma virens enables faster aerobic growth of S. cerevisiae on xylodextrins compared to CDT-2. ST16 is a xylodextrin-specific transporter, and the xylobiose transport activity of ST16 is not inhibited by cellobiose. Other transporters identified in the screen also enable growth on xylodextrins including xylotriose. Taken together, these results indicate that multiple transporters might prove useful to improve xylodextrin utilization in S. cerevisiae. Efforts to use directed evolution to improve ST16 from a chromosomally-integrated copy were not successful, due to background growth of yeast on other carbon sources present in the selection medium. Future experiments will require increasing the baseline growth rate of the yeast population on xylodextrins, to ensure that the selective pressure exerted on xylodextrin transport can lead to isolation of improved xylodextrin transporters.


2018 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Hidayatullah Mahar ◽  
Abdul Sattar Jatoi ◽  
Imran Nazir Unar ◽  
Irshad Ali Gopang ◽  
Makhdoom Naeem ◽  
...  

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 515-522
Author(s):  
L P Wakem ◽  
F Sherman

Abstract Approximately 290 omnipotent suppressors, which enhance translational misreading, were isolated in strains of the yeast Saccharomyces cerevisiae containing the psi+ extrachromosomal determinant. The suppressors could be assigned to 8 classes by their pattern of suppression of five nutritional markers. The suppressors were further distinguished by differences in growth on paromomycin medium, hypertonic medium, low temperatures (10 degrees), nonfermentable carbon sources, alpha-aminoadipic acid medium, and by their dominance and recessiveness. Genetic analysis of 12 representative suppressors resulted in the assignment of these suppressors to 6 different loci, including the three previously described loci SUP35 (chromosome IV), SUP45 (chromosome II) and SUP46 (chromosome II), as well as three new loci SUP42 (chromosome IV), SUP43 (chromosome XV) and SUP44 (chromosome VII). Suppressors belonging to the same locus had a wide range of different phenotypes. Differences between alleles of the same locus and similarities between alleles of different loci suggest that the omnipotent suppressors encode proteins that effect different functions and that altered forms of each of the proteins can effect the same function.


BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jean F. Challacombe ◽  
Cedar N. Hesse ◽  
Lisa M. Bramer ◽  
Lee Ann McCue ◽  
Mary Lipton ◽  
...  

Abstract Background The dominant fungi in arid grasslands and shrublands are members of the Ascomycota phylum. Ascomycota fungi are important drivers in carbon and nitrogen cycling in arid ecosystems. These fungi play roles in soil stability, plant biomass decomposition, and endophytic interactions with plants. They may also form symbiotic associations with biocrust components or be latent saprotrophs or pathogens that live on plant tissues. However, their functional potential in arid soils, where organic matter, nutrients and water are very low or only periodically available, is poorly characterized. Results Five Ascomycota fungi were isolated from different soil crust microhabitats and rhizosphere soils around the native bunchgrass Pleuraphis jamesii in an arid grassland near Moab, UT, USA. Putative genera were Coniochaeta, isolated from lichen biocrust, Embellisia from cyanobacteria biocrust, Chaetomium from below lichen biocrust, Phoma from a moss microhabitat, and Aspergillus from the soil. The fungi were grown in replicate cultures on different carbon sources (chitin, native bunchgrass or pine wood) relevant to plant biomass and soil carbon sources. Secretomes produced by the fungi on each substrate were characterized. Results demonstrate that these fungi likely interact with primary producers (biocrust or plants) by secreting a wide range of proteins that facilitate symbiotic associations. Each of the fungal isolates secreted enzymes that degrade plant biomass, small secreted effector proteins, and proteins involved in either beneficial plant interactions or virulence. Aspergillus and Phoma expressed more plant biomass degrading enzymes when grown in grass- and pine-containing cultures than in chitin. Coniochaeta and Embellisia expressed similar numbers of these enzymes under all conditions, while Chaetomium secreted more of these enzymes in grass-containing cultures. Conclusions This study of Ascomycota genomes and secretomes provides important insights about the lifestyles and the roles that Ascomycota fungi likely play in arid grassland, ecosystems. However, the exact nature of those interactions, whether any or all of the isolates are true endophytes, latent saprotrophs or opportunistic phytopathogens, will be the topic of future studies.


Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 530 ◽  
Author(s):  
Bao-Teng Wang ◽  
Shuang Hu ◽  
Xing-Ye Yu ◽  
Long Jin ◽  
Yun-Jia Zhu ◽  
...  

Polysaccharides are biopolymers made up of a large number of monosaccharides joined together by glycosidic bonds. Polysaccharides are widely distributed in nature: Some, such as peptidoglycan and cellulose, are the components that make up the cell walls of bacteria and plants, and some, such as starch and glycogen, are used as carbohydrate storage in plants and animals. Fungi exist in a variety of natural environments and can exploit a wide range of carbon sources. They play a crucial role in the global carbon cycle because of their ability to break down plant biomass, which is composed primarily of cell wall polysaccharides, including cellulose, hemicellulose, and pectin. Fungi produce a variety of enzymes that in combination degrade cell wall polysaccharides into different monosaccharides. Starch, the main component of grain, is also a polysaccharide that can be broken down into monosaccharides by fungi. These monosaccharides can be used for energy or as precursors for the biosynthesis of biomolecules through a series of enzymatic reactions. Industrial fermentation by microbes has been widely used to produce traditional foods, beverages, and biofuels from starch and to a lesser extent plant biomass. This review focuses on the degradation and utilization of plant homopolysaccharides, cellulose and starch; summarizes the activities of the enzymes involved and the regulation of the induction of the enzymes in well-studied filamentous fungi.


2008 ◽  
Vol 74 (24) ◽  
pp. 7514-7521 ◽  
Author(s):  
Sanom Nonklang ◽  
Babiker M. A. Abdel-Banat ◽  
Kamonchai Cha-aim ◽  
Nareerat Moonjai ◽  
Hisashi Hoshida ◽  
...  

ABSTRACT We demonstrate herein the ability of Kluyveromyces marxianus to be an efficient ethanol producer and host for expressing heterologous proteins as an alternative to Saccharomyces cerevisiae. Growth and ethanol production by strains of K. marxianus and S. cerevisiae were compared under the same conditions. K. marxianus DMKU3-1042 was found to be the most suitable strain for high-temperature growth and ethanol production at 45°C. This strain, but not S. cerevisiae, utilized cellobiose, xylose, xylitol, arabinose, glycerol, and lactose. To develop a K. marxianus DMKU3-1042 derivative strain suitable for genetic engineering, a uracil auxotroph was isolated and transformed with a linear DNA of the S. cerevisiae ScURA3 gene. Surprisingly, Ura+ transformants were easily obtained. By Southern blot hybridization, the linear ScURA3 DNA was found to have inserted randomly into the K. marxianus genome. Sequencing of one Lys− transformant confirmed the disruption of the KmLYS1 gene by the ScURA3 insertion. A PCR-amplified linear DNA lacking K. marxianus sequences but containing an Aspergillus α-amylase gene under the control of the ScTDH3 promoter together with an ScURA3 marker was subsequently used to transform K. marxianus DMKU3-1042 in order to obtain transformants expressing Aspergillus α-amylase. Our results demonstrate that K. marxianus DMKU3-1042 can be an alternative cost-effective bioethanol producer and a host for transformation with linear DNA by use of S. cerevisiae-based molecular genetic tools.


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