Dataset Information

From mannan to bioethanol: cell surface co-display of ?-mannanase and ?-mannosidase on yeast Saccharomyces cerevisiae.

ABSTRACT: BACKGROUND:Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays ?-mannanase and ?-mannosidase; this strain is expected to facilitate ethanol fermentation using mannan as a biomass source. RESULTS:Parental yeast S. cerevisiae assimilated mannose and glucose as monomeric sugars, producing ethanol from mannose. We constructed yeast strains that express tethered ?-mannanase and ?-mannosidase; co-display of the two enzymes on the cell surface was confirmed by immunofluorescence staining and enzyme activity assays. The constructed yeast cells successfully hydrolyzed 1,4-?-d-mannan and produced ethanol by assimilating the resulting mannose without external addition of enzymes. Furthermore, the constructed strain produced ethanol from 1,4-?-d-mannan continually during the third batch of repeated fermentation. Additionally, the constructed strain produced ethanol from ivory nut mannan; ethanol yield was improved by NaOH pretreatment of the substrate. CONCLUSIONS:We successfully displayed ?-mannanase and ?-mannosidase on the yeast cell surface. Our results clearly demonstrate the utility of the strain co-displaying ?-mannanase and ?-mannosidase for ethanol fermentation from mannan biomass. Thus, co-tethering ?-mannanase and ?-mannosidase on the yeast cell surface provides a powerful platform technology for yeast fermentation toward the production of bioethanol and other biochemicals from lignocellulosic materials containing mannan components.

SUBMITTER: Ishii J

PROVIDER: S-EPMC5009545 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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From mannan to bioethanol: cell surface co-display of β-mannanase and β-mannosidase on yeast Saccharomyces cerevisiae.

Ishii Jun J Okazaki Fumiyoshi F Djohan Apridah Cameliawati AC Hara Kiyotaka Y KY Asai-Nakashima Nanami N Teramura Hiroshi H Andriani Ade A Tominaga Masahiro M Wakai Satoshi S Kahar Prihardi P Yopi Prasetya Bambang B Ogino Chiaki C Kondo Akihiko A

Biotechnology for biofuels 20160902 1

<h4>Background</h4>Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays β-mannanase and β-mannosidase; th ...[more]

PMID: 27594915

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Project description:In the search for renewable sources of energy, bioethanol stands out as a benchmark biofuel because its production is based on a proven technological platform. Bioethanol is produced mainly from the fermentation of carbohydrates derived from agricultural feedstocks by the yeast Saccharomyces cerevisiae. One of the most widely adopted strains is PE-2, a heterothallic diploid naturally adapted to the sugar cane fermentation process used in Brazil. Here we report the molecular genetic analysis of a PE-2 derived diploid (JAY270), and the complete genome sequence of a haploid derivative (JAY291). The JAY270 genome is highly heterozygous (~2 SNPs per kilobase), and has several structural polymorphisms between homologous chromosomes. These chromosomal rearrangements are confined to the peripheral regions of the chromosomes, and appear to reflect ectopic homologous recombination between repetitive DNA sequences. Despite the complex karyotype of JAY270, this diploid, when sporulated, had a high frequency of viable spores (~93%). Crosses of haploids derived from JAY270 to a haploid of the unrelated laboratory strain S288c also resulted in diploids that had good spore viability (75-95%). Thus, the rearrangements that exist near the ends of chromosomes do not impair meiosis and spore viability, as they do not span regions that contain essential genes. This observation is consistent with a model in which the peripheral regions of chromosomes represent plastic domains of the genome that are free to recombine ectopically and experiment with alternative structures that may be associated with a fitness benefit. We also explore features of the JAY270 and JAY291 genomes that help explain their high adaptation to industrial environments, exhibiting desirable phenotypes such as high cell mass production and fermentation kinetics, high temperature growth and oxidative stress tolerance. The genomic manipulation of such strains could enable the creation a new generation of industrial organisms, ideally suited for use as delivery vehicles for future bioenergy technologies.

Project description:BackgroundEnvironmental stresses and inhibitors encountered by Saccharomyces cerevisiae strains are the main limiting factors in bioethanol fermentation. Strains with different genetic backgrounds usually show diverse stress tolerance responses. An understanding of the mechanisms underlying these phenotypic diversities within S. cerevisiae populations could guide the construction of strains with desired traits.ResultsWe explored the genetic characteristics of the bioethanol S. cerevisiae strain YJS329 and elucidated how genetic variations in its genome were correlated with specified traits compared to similar traits in the S288c-derived strain, BYZ1. Karyotypic electrophoresis combined with array-comparative genomic hybridization indicated that YJS329 was a diploid strain with a relatively constant genome as a result of the fewer Ty elements and lack of structural polymorphisms between homologous chromosomes that it contained. By comparing the sequence with the S288c genome, a total of 64,998 SNPs, 7,093 indels and 11 unique genes were identified in the genome of YJS329-derived haploid strain YJSH1 through whole-genome sequencing. Transcription comparison using RNA-Seq identified which of the differentially expressed genes were the main contributors to the phenotypic differences between YJS329 and BYZ1. By combining the results obtained from the genome sequences and the transcriptions, we predicted how the SNPs, indels and chromosomal copy number variations may affect the mRNA expression profiles and phenotypes of the yeast strains. Furthermore, some genetic breeding strategies to improve the adaptabilities of YJS329 were designed and experimentally verified.ConclusionsThrough comparative functional genomic analysis, we have provided some insights into the mechanisms underlying the specific traits of the bioenthanol strain YJS329. The work reported here has not only enriched the available genetic resources of yeast but has also indicated how functional genomic studies can be used to improve genetic breeding in yeast.

Dataset Information

From mannan to bioethanol: cell surface co-display of ?-mannanase and ?-mannosidase on yeast Saccharomyces cerevisiae.

Publications

From mannan to bioethanol: cell surface co-display of β-mannanase and β-mannosidase on yeast Saccharomyces cerevisiae.

Similar Datasets

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