Limits...
Screening of microorganisms producing cold-active oxidoreductases to be applied in enantioselective alcohol oxidation. An Antarctic survey.

Araújo LS, Kagohara E, Garcia TP, Pellizari VH, Andrade LH - Mar Drugs (2011)

Bottom Line: Among the identified microorganisms, Flavobacterium sp. and Arthrobacter sp. showed excellent enzymatic activity.From these studies, it was observed that Flavobacterium sp. has an excellent enzymatic activity at 10 °C and Arthrobacter sp. at 15 and 25 °C.We have also determined the growth curves of these bacteria, and both strains showed optimum growth at 25 °C, indicating that these bacteria are psychrotroph.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, SP 05508-900 São Paulo, Brazil.

ABSTRACT
Several microorganisms were isolated from soil/sediment samples of Antarctic Peninsula. The enrichment technique using (RS)-1-(phenyl)ethanol as a carbon source allowed us to isolate 232 psychrophile/psychrotroph microorganisms. We also evaluated the enzyme activity (oxidoreductases) for enantioselective oxidation reactions, by using derivatives of (RS)-1-(phenyl)ethanol as substrates. Among the studied microorganisms, 15 psychrophile/psychrotroph strains contain oxidoreductases that catalyze the (S)-enantiomer oxidation from racemic alcohols to their corresponding ketones. Among the identified microorganisms, Flavobacterium sp. and Arthrobacter sp. showed excellent enzymatic activity. These new bacteria strains were selected for optimization study, in which the (RS)-1-(4-methyl-phenyl)ethanol oxidation was evaluated in several reaction conditions. From these studies, it was observed that Flavobacterium sp. has an excellent enzymatic activity at 10 °C and Arthrobacter sp. at 15 and 25 °C. We have also determined the growth curves of these bacteria, and both strains showed optimum growth at 25 °C, indicating that these bacteria are psychrotroph.

Show MeSH
Deracemisation process mediated by Flavobacterium sp. (HK1D9).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3111190&req=5

f4-marinedrugs-09-00889: Deracemisation process mediated by Flavobacterium sp. (HK1D9).

Mentions: When the bacterial growing and reactions were performed at 15 °C and 25 °C (Flavobacterium sp.) excellent oxidoreductase activities were observed. The best conversion of the (RS)-alcohol 2 to ketone (45%) was obtained after 24 h reaction at 25 °C (Table 3, Entry 13,). Along the reaction, there was a few decrease in ketone concentration and an increase in (R)-1-(4-methylphenyl)ethanol concentration and, consequently its enantiomeric excess (Table 3, Entries 13–15). In an oxidative kinetic resolution process, the ratio of the ketone and a single alcohol enantiomer concentration should be 1:1. The above mentioned behavior indicates the presence of ketoreductase that catalyzes enantioselectively the reduction of the produced 4-methylacetophenone to the (R)-1-(4-methylphenyl)ethanol, resulting in a higher (R)-alcohol concentratrion than 50%. This process can be called as deracemisation (Scheme 2).


Screening of microorganisms producing cold-active oxidoreductases to be applied in enantioselective alcohol oxidation. An Antarctic survey.

Araújo LS, Kagohara E, Garcia TP, Pellizari VH, Andrade LH - Mar Drugs (2011)

Deracemisation process mediated by Flavobacterium sp. (HK1D9).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3111190&req=5

f4-marinedrugs-09-00889: Deracemisation process mediated by Flavobacterium sp. (HK1D9).
Mentions: When the bacterial growing and reactions were performed at 15 °C and 25 °C (Flavobacterium sp.) excellent oxidoreductase activities were observed. The best conversion of the (RS)-alcohol 2 to ketone (45%) was obtained after 24 h reaction at 25 °C (Table 3, Entry 13,). Along the reaction, there was a few decrease in ketone concentration and an increase in (R)-1-(4-methylphenyl)ethanol concentration and, consequently its enantiomeric excess (Table 3, Entries 13–15). In an oxidative kinetic resolution process, the ratio of the ketone and a single alcohol enantiomer concentration should be 1:1. The above mentioned behavior indicates the presence of ketoreductase that catalyzes enantioselectively the reduction of the produced 4-methylacetophenone to the (R)-1-(4-methylphenyl)ethanol, resulting in a higher (R)-alcohol concentratrion than 50%. This process can be called as deracemisation (Scheme 2).

Bottom Line: Among the identified microorganisms, Flavobacterium sp. and Arthrobacter sp. showed excellent enzymatic activity.From these studies, it was observed that Flavobacterium sp. has an excellent enzymatic activity at 10 °C and Arthrobacter sp. at 15 and 25 °C.We have also determined the growth curves of these bacteria, and both strains showed optimum growth at 25 °C, indicating that these bacteria are psychrotroph.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, SP 05508-900 São Paulo, Brazil.

ABSTRACT
Several microorganisms were isolated from soil/sediment samples of Antarctic Peninsula. The enrichment technique using (RS)-1-(phenyl)ethanol as a carbon source allowed us to isolate 232 psychrophile/psychrotroph microorganisms. We also evaluated the enzyme activity (oxidoreductases) for enantioselective oxidation reactions, by using derivatives of (RS)-1-(phenyl)ethanol as substrates. Among the studied microorganisms, 15 psychrophile/psychrotroph strains contain oxidoreductases that catalyze the (S)-enantiomer oxidation from racemic alcohols to their corresponding ketones. Among the identified microorganisms, Flavobacterium sp. and Arthrobacter sp. showed excellent enzymatic activity. These new bacteria strains were selected for optimization study, in which the (RS)-1-(4-methyl-phenyl)ethanol oxidation was evaluated in several reaction conditions. From these studies, it was observed that Flavobacterium sp. has an excellent enzymatic activity at 10 °C and Arthrobacter sp. at 15 and 25 °C. We have also determined the growth curves of these bacteria, and both strains showed optimum growth at 25 °C, indicating that these bacteria are psychrotroph.

Show MeSH