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A new search for thermotolerant yeasts, its characterization and optimization using response surface methodology for ethanol production.

Arora R, Behera S, Sharma NK, Kumar S - Front Microbiol (2015)

Bottom Line: However, the technologies in use have some drawbacks including incapability of pentose fermentation, reduced tolerance to products formed, costly processes, etc.After optimization using Face-centered Central Composite Design (FCCD), the growth parameters like temperature and pH were found to be 45.17°C and 5.49, respectively for K. marxianus NIRE-K1 and 45.41°C and 5.24, respectively for K. marxianus NIRE-K3.Ethanol yield (Y x∕s ), sugar to ethanol conversion rate (%), microbial biomass concentration (X) and volumetric product productivity (Q p ) obtained by K. marxianus NIRE-K3 were found to be 9.3, 9.55, 14.63, and 31.94% higher than that of K. marxianus NIRE-K1, respectively.

View Article: PubMed Central - PubMed

Affiliation: Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy Kapurthala, India ; I.K Gujral Punjab Technical University Kapurthala, India.

ABSTRACT
The progressive rise in energy crisis followed by green house gas (GHG) emissions is serving as the driving force for bioethanol production from renewable resources. Current bioethanol research focuses on lignocellulosic feedstocks as these are abundantly available, renewable, sustainable and exhibit no competition between the crops for food and fuel. However, the technologies in use have some drawbacks including incapability of pentose fermentation, reduced tolerance to products formed, costly processes, etc. Therefore, the present study was carried out with the objective of isolating hexose and pentose fermenting thermophilic/thermotolerant ethanologens with acceptable product yield. Two thermotolerant isolates, NIRE-K1 and NIRE-K3 were screened for fermenting both glucose and xylose and identified as Kluyveromyces marxianus NIRE-K1 and K. marxianus NIRE-K3. After optimization using Face-centered Central Composite Design (FCCD), the growth parameters like temperature and pH were found to be 45.17°C and 5.49, respectively for K. marxianus NIRE-K1 and 45.41°C and 5.24, respectively for K. marxianus NIRE-K3. Further, batch fermentations were carried out under optimized conditions, where K. marxianus NIRE-K3 was found to be superior over K. marxianus NIRE-K1. Ethanol yield (Y x∕s ), sugar to ethanol conversion rate (%), microbial biomass concentration (X) and volumetric product productivity (Q p ) obtained by K. marxianus NIRE-K3 were found to be 9.3, 9.55, 14.63, and 31.94% higher than that of K. marxianus NIRE-K1, respectively. This study revealed the promising potential of both the screened thermotolerant isolates for bioethanol production.

No MeSH data available.


Related in: MedlinePlus

Phylogenetic tree drawn through BLAST showing genetic relationship between K. marxianus NIRE-K3 and similar organisms.
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Figure 5: Phylogenetic tree drawn through BLAST showing genetic relationship between K. marxianus NIRE-K3 and similar organisms.

Mentions: The phylogenetic tree is the study of evolutionary relatedness between the species. In this study, phylogenetic tree was drawn on the basis of distance matrix of homology sequence of similar microorganisms by BLAST where isolate NIRE-K1 was found to be related to the ascomycetes group and have maximum homology similarity with K. marxianus strain CHY1612 which has been depicted in Figure 4. Similarly, other isolate NIRE-K3 showed maximum similarity with both the strains of K. marxianus 1.2 18S and K. marxianus B.WHX.12 (Figure 5). Further, sequence of NIRE-K1 is the substem of K. marxianus DMKU3-1042 with 99% homology. Therefore, on the basis of the above similarity, the isolate NIRE-K1 and NIRE-K3 were confirmed as the K. marxianus which were named as K. marxianus NIRE-K1 and K. marxianus NIRE-K3.


A new search for thermotolerant yeasts, its characterization and optimization using response surface methodology for ethanol production.

Arora R, Behera S, Sharma NK, Kumar S - Front Microbiol (2015)

Phylogenetic tree drawn through BLAST showing genetic relationship between K. marxianus NIRE-K3 and similar organisms.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555967&req=5

Figure 5: Phylogenetic tree drawn through BLAST showing genetic relationship between K. marxianus NIRE-K3 and similar organisms.
Mentions: The phylogenetic tree is the study of evolutionary relatedness between the species. In this study, phylogenetic tree was drawn on the basis of distance matrix of homology sequence of similar microorganisms by BLAST where isolate NIRE-K1 was found to be related to the ascomycetes group and have maximum homology similarity with K. marxianus strain CHY1612 which has been depicted in Figure 4. Similarly, other isolate NIRE-K3 showed maximum similarity with both the strains of K. marxianus 1.2 18S and K. marxianus B.WHX.12 (Figure 5). Further, sequence of NIRE-K1 is the substem of K. marxianus DMKU3-1042 with 99% homology. Therefore, on the basis of the above similarity, the isolate NIRE-K1 and NIRE-K3 were confirmed as the K. marxianus which were named as K. marxianus NIRE-K1 and K. marxianus NIRE-K3.

Bottom Line: However, the technologies in use have some drawbacks including incapability of pentose fermentation, reduced tolerance to products formed, costly processes, etc.After optimization using Face-centered Central Composite Design (FCCD), the growth parameters like temperature and pH were found to be 45.17°C and 5.49, respectively for K. marxianus NIRE-K1 and 45.41°C and 5.24, respectively for K. marxianus NIRE-K3.Ethanol yield (Y x∕s ), sugar to ethanol conversion rate (%), microbial biomass concentration (X) and volumetric product productivity (Q p ) obtained by K. marxianus NIRE-K3 were found to be 9.3, 9.55, 14.63, and 31.94% higher than that of K. marxianus NIRE-K1, respectively.

View Article: PubMed Central - PubMed

Affiliation: Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy Kapurthala, India ; I.K Gujral Punjab Technical University Kapurthala, India.

ABSTRACT
The progressive rise in energy crisis followed by green house gas (GHG) emissions is serving as the driving force for bioethanol production from renewable resources. Current bioethanol research focuses on lignocellulosic feedstocks as these are abundantly available, renewable, sustainable and exhibit no competition between the crops for food and fuel. However, the technologies in use have some drawbacks including incapability of pentose fermentation, reduced tolerance to products formed, costly processes, etc. Therefore, the present study was carried out with the objective of isolating hexose and pentose fermenting thermophilic/thermotolerant ethanologens with acceptable product yield. Two thermotolerant isolates, NIRE-K1 and NIRE-K3 were screened for fermenting both glucose and xylose and identified as Kluyveromyces marxianus NIRE-K1 and K. marxianus NIRE-K3. After optimization using Face-centered Central Composite Design (FCCD), the growth parameters like temperature and pH were found to be 45.17°C and 5.49, respectively for K. marxianus NIRE-K1 and 45.41°C and 5.24, respectively for K. marxianus NIRE-K3. Further, batch fermentations were carried out under optimized conditions, where K. marxianus NIRE-K3 was found to be superior over K. marxianus NIRE-K1. Ethanol yield (Y x∕s ), sugar to ethanol conversion rate (%), microbial biomass concentration (X) and volumetric product productivity (Q p ) obtained by K. marxianus NIRE-K3 were found to be 9.3, 9.55, 14.63, and 31.94% higher than that of K. marxianus NIRE-K1, respectively. This study revealed the promising potential of both the screened thermotolerant isolates for bioethanol production.

No MeSH data available.


Related in: MedlinePlus