Atsuo Nishimura

Identification of algal transformation products from alicyclic ketones

Abstract Algal transformations of four alicyclic ketones were photoautotrophically studied with an axenic strain of Chlorella pyrenoidosa Chick. The algal reduction of 2-, 3- and 4-methylcyclohexanones, and 4- tert -butyl-cyclohexanone to form the corresponding cis - and trans -alcohols were confirmed by GC-MS analysis. The cis/trans ratios of the resulting cyclohexanols were different from those obtained by reduction with Aspergillus repens . The ratio of cis -isomer to trans -one of 3-methylcyclohexanol was especially large (20:1).

Metabolism of n-alkylcyclohexanes with an even number of carbon atoms in the side chain by Micrococcus sp. RCO-4M

The metabolism of n-alkyleyclohexanes with an even number of carbon atoms (6, 8, 10, 12, 14) in the side chain by Micrococcus sp. RCO-4M was investigated. Evidence for the formation of cyclohexanecarboxylic acid (I), cyclohexaneacetic acid (II), 1-cyclohexenecarboxylic acid (III), 6-hydroxyhexanoic acid (IV), adipic acid (V), and trans-4-hydroxycyclohexaneacetic acid (VI) is presented. The presence of products (II), (IV) and (V) especially represent the complete degradation of n-alkylcyclohexanes with an even number of carbon atoms in the side chain by a single organism. The occurrence of a newly-identified product (VI) suggests that a new metabolic pathway for n-alkylcyclohexanes with even-carbon-number side chain operates in this organism.

Microbial reduction of cyclohexanone by Chlorella pyrenoidosa chick

Algal transformation of cyclohexanone (C6ON) was photoautotrophically studied with an axenic strain of Chlorella pyrenoidosa Chick. The algal reduction of C6ON to cyclohexanol (C6OL) was confirmed by GC-MS analysis, but C6OL could not be further transformed by this strain. Three cycloalkanones, cyclopentanone, cycloheptanone, and cyclooctanone, were also converted to their corresponding alcohols in a growing culture of the same strain. The pH of the medium did not influence the algal reduction of C6ON to C6OL, although increasing C6ON concentrations resulted in a decrease in cell growth. The maximum accumulation of C6OL in growing culture was observed at 0.2% C6ON.

Biotransformation of cyclic β-keto esters by Chlorella pyrenoidosa Chick

Abstract Algal transformations of three cyclic β-keto esters, methyl 2-oxocyclopentanecarboxylate (MCPC), ethyl 2-oxocyclohexanecarboxylate (ECHxC), and methyl 2-oxocycloheptanecarboxylate (MCHpC) were photoautotrophically studied with an axenic strain of Chlorella pyrenoidosa Chick. The three cyclic β-keto esters were transformed in two manners; reduction of the carbonyl group to a hydroxy group and elimination of the alkoxycarbonyl group. The former reaction occurred more often than the latter. The cis/trans ratios of the resulting alcohols in MCPC, ECHxC and MCHpC were 13 : 87, 15 : 85, and 65 : 35, respectively. The alkoxycarbonyl group elimination products were as follows: cyclopentanone and cyclopentanol in MCPC, cyclohexanone and cyclohexanol in ECHxC, and cycloheptanone in MCHpC.

Bioconversion of cyclohexaneacetic acid to monohydroxycyclohexaneacetic acids by Chlorella pyrenoidosa chick

Abstract Algal conversion of cyclohexaneacetic acid was studied with five axenic strains of Chlorella ; in two Chlorella pyrenoidosa strains, cyclohexaneacetic acid was transformed to three monohydroxycyclohexaneacetic acids. As biotransformation products, cis - and trans -3-hydroxycyclohexaneacetic acid and trans -4-hydroxycyclohexaneacetic acid were identified by gas chromatography-mass spectrometry.

Studies on Biosynthesis on Biotin by Microorganisms: Part I. Accumulation of Biotin-Vitamers by Various MicroorganismsPart II. Identification of Biotin-Vitamers Accumulated by Various Microorganisms

The accumulation of biotin-vitamers in the culture media of a large number of microorganisms (about 700 strains) was studied. The contents of the biotin-vitamers were quantitatively determined by microbiological assays with Lactobacillus arabinosus and Saccharomyces cerevisiae.It was found that large amounts of biotin-vitamers were accumulated by various microorganisms such as Streptomyces, molds and bacteria, and that the yield of biotin-vitamers was enhanced by the addition of pimelic acid or azelaic acid to the media. It was also found that the main portion of the vitamers accumulated by many microorganisms did not support the growth of Lactobacillus arabinosus, while it did support that of Saccharomyces cerevisiae. The small amounts of true biotin were observed in the culture media of various Streptomyces and molds, but hardly in the culture media of bacteria.The identification of biotin-vitamers accumulated by various microorganisms is described, and the distribution of the vitamers in microorganisms...

Stimulatory Effect of Acetate and Propionate on Aspergillic Acid Formation by Aspergillus oryzae A 21

Abstract The stimulatory effect of acetate and propionate on the formation of aspergillic acid (AA) by Aspergillus oryzae A 21 was investigated. 14C labeled AA with a high specific activity was biosynthesized from [2-14C]propionate or [1-14C]acetate in a medium without leucine and isoleucine, precursors in the biosynthesis of AA. Incorporation of three intact acetate units derived from [1,2-13C]acetate into AA via leucine and isoleucine was demonstrated by 13C NMR analyses. Furthermore, a depressive effect of propionate on the catabolism of leucine and isoleucine was assumed to bring about the increase in the formation of AA.

Microbial degradation of aspergillic acid by Trichoderma koningii M 102

Abstract A microorganism, strain M 102, capable of degrading aspergillic acid (AA), was first isolated from a soil sample in a drainage ditch and was identified as Trichoderma koningii Oudemans. This fungus degraded AA, but not hydroxyaspergillic acid (HAA) or deoxyaspergillic acid (DAA). The AA-degrading ability of M 102 was induced by incubation with AA but not with HAA or DAA. AA-degradation activity was found in a crude enzyme prepared from the mycelia induced by AA; this AA degradation reaction required NAD(P)H and oxygen.

Metabolism of n-alkyl-substituted cyclohexanes with an odd number of carbon atoms in the side chain by Micrococcus sp. RCO-4M

The metabolism of n-alkyl-substituted cyclohexanes (n-ACH) with an odd number of carbon atoms (7, 9, 11) in the side chain by Micrococcus sp. RCO-4M was investigated. Evidence for the formation of cyclohexanecarboxylic acid (C6CA), 1-cyclohexenecarboxylic acid (1-ene-C6CA), and trans-4-hydroxycyclohexanecarboxylic acid (t-4-OH-C6CA) is presented. A large amount of C6CA, 1-ene-C6CA and the small quantity of t-4-OH-C6CA were accumulated in culture broth. It is suggested that Micrococcus sp. RCO-4M metabolized n-ACH with an odd number of carbon atoms in the side chain to C6CA by beta-oxidation of the side chain and furthermore degraded C6CA by two pathways involving 1-ene-C6CA and t-4-OH-C6CA as key intermediates.

Identification of the degradation products of aspergillic acid by Trichoderma koningii M 102

Abstract Isolation and identification of the degradation products of aspergillic acid, a secondary metabolite of fungi, by Trichoderma koningii M 102 were undertaken. 14 C-labeling experiments indicated that aspergillic acid was broken-down to a water-soluble degradation product and a chloroform-soluble one. Consequently, leucine and a new microbial metabolite, 2-hydroxyimino-3-methyl-1-pentanol, were isolated and identified as the degradation products formed by cleavage of the pyrazine ring of aspergillic acid by T. koningii M 102.