Alcohol dehydrogenases from thermophilic and hyperthermophilic archaea and bacteria

Many studies have been undertaken to characterise alcohol dehydrogenases (ADHs) from thermophiles and hyperthermophiles, mainly to better understand their activities and thermostability. To date, there are 20 thermophilic archaeal and 17 thermophilic bacterial strains known to have ADHs or similar enzymes, including the hypothetical proteins. Some of these thermophiles are found to have multiple ADHs, sometimes of different types. A rigid delineation of amino acid sequences amongst currently elucidated thermophilic ADHs and similar proteins is phylogenetically apparent. All are NAD(P)-dependent, with one exception that utilises the cofactor F420 instead. Within the NAD(P)-dependent group, the thermophilic ADHs are orderly clustered as zinc-dependent ADHs, short-chain ADHs, and iron-containing/activated ADHs. Distance matrix calculations reveal that thermophilic ADHs within one type are homologous, with those derived from a single genus often showing high similarities. Elucidation of the enzyme activity and stability, coupled with structur

Bacterial community structure and physiological state in a biofilm reactor degrading 4-chloroaniline

Degradation of 4-chloroaniline in the presence of aniline by a microbial community in a laboratory-scale biofilm reactor was evaluated. The starter inoculum was isolated and reconstructed from a percolating column enrichment of Indonesian agricultural soil. The capacity to mineralise and detoxify 4-chloroaniline in the presence of aniline was demonstrated by the biofilm reactor when operated at high hydraulic retention time (HRT; 0.87 h). At low HRT (0.23 h and 0.39 h) 4-chlorocatechol accumulated in the effluent, accompanied by a decrease in dechlorination and detoxification. When returned to high HRT (2.14 h), the accumulation of 4-chlorocatechol stopped and the extent of dechlorination and detoxification increased. Bacteria other than the original inoculum appeared in the reactor when the operating mode was switched from closed cycle to open cycle. One of these bacteria, identified as Pseudomonas putida RI by partial 16S rDNA sequencing, subsequently dominated the reactor at every HRT imposed. PCR-based single-strand conformational polymorphism of 16 s rDNA and traditional cultivation procedures indicated that the bacterial composition in the reactor shifted in response to applied HRT. The relationship between the bacterial abundance and the degradation capacity of the reactor is discussed

Coenzyme Q10 production from marine bacteria

Disclosed are methods, compounds and compositions related to the production of coenzyme

Critical assessment of various techniques for the extraction of carotenoids and co-enzyme Q10 from the Thraustochytrid strain ONC-T18

A variety of techniques for extracting carotenoids from the marine Thraustochytrium sp. ONC-T18 was compared. Specifically, the organic solvents acetone, ethyl acetate, and petroleum ether were tested, along with direct and indirect ultrasonic assisted extraction (probe vs bath) methods. Techniques that used petroleum ether/acetone/water (15:75:10, v/v/v) with 3 h of agitation, or 5 min in an ultrasonic bath, produced the highest extraction yields of total carotenoids (29&minus;30.5 &mu;g g-1). Concentrations up to 11.5 &mu;g g-1 of canthaxanthin and 17.5 &mu;g g-1 of &beta;-carotene were detected in extracts stored for 6 weeks. Astaxanthin and echinenone were also detected as minor compounds. Extracts with and without antioxidants showed similar carotenoid concentration profiles. However, total carotenoid concentrations were approximately 8% higher when antioxidants were used. Finally, an easy-to-perform and inexpensive method to detect co-enzymes in ONC-T18 was also developed using silica gel TLC plates. Five percent methanol in toluene as a mobile phase consistently eluted co-enzyme Q10 standards and could separate the co-enzyme fractions present in ONC-T18. <br /

Eukaryotic microorganisms for producing lipids and antioxidants

Disclosed are compositions and methods related to eukaryotic microorganisms that can produce unsaturated fatty acids which can be purified and used

Optimization of fatty acid determination in selected fish and microalgal oils

The use of ten fatty acid methyl ester reference standards coupled with a detailed quantification method was shown to significantly optimize the fatty acid determination of selected fish and microalgal oils when compared to methods that use only one reference standard (C19:0 or C23:0) as a relative response factor. When using the mixture of ten reference standards after transesterifying oils with NaOH/BF3, determination of total fatty acids, eicosapentaenoic acid and docosahexaenoic acid improved by an average of 7.3, 11.5 and 8.4%, respectively. Furthermore, improvements of 13.9, 18.9 and 6.8% of total fatty acids, EPA and DHA, respectively, were obtained when using the mixture of reference standards for fatty acid determination after directly extracting and transesterifying oil contained in microalgal cells with a mixture of methanol, HCl and chloroform. Fatty acid methyl ester standards dissolved in isooctane showed &lt;5% variability throughout 130 days of stability testing when stored at &minus;20 &deg;C. The optimized method can be used for improving the quantification of fatty acids in both oils (fish and microalgal oils) and dry microalgal cells.<br /

Characterization of a soil-derived bacterial consortium degrading 4-chloroaniline

A bacterial consortium comprising four different species was isolated from an Indonesian agricultural soil using a mixture of aniline and 4-chloroaniline (4CA) as principal carbon sources. The four species were identified as Chryseobacterium indologenes SB1, Comamonas testosteroni SB2, Pseudomonas corrugata SB4 and Stenotrophomonas maltophilia SB5. Growth studies on aniline and 4CA as single and mixed substrates demonstrated that the bacteria preferred to grow on and utilize aniline rather than 4CA, although both compounds were eventually depleted from the culture supernatant. However, despite 100 % disappearance of the parent substrates, the degradation of 4CA was always characterized by incomplete dechlorination and 4-chlorocatechol accumulation. This result suggests that further degradation of 4-chlorocatechol may be the rate-limiting step in the metabolism of 4CA by the bacterial consortium. HPLC-UV analysis showed that 4-chlorocatechol was further degraded via an ortho-cleavage pathway by the bacterial consortium. This hypothesis was supported by the results from enzyme assays of the crude cell extract of the consortium revealing catechol 1,2-dioxygenase activity which converted catechol and 4-chlorocatechol to cis,cis-muconic acid and 3-chloro-cis,cis-muconic acid respectively. However, the enzyme had a much higher conversion rate for catechol [156 U (g protein)(-1)] than for 4-chlorocatechol [17.2 U (g protein)(-1)], indicating preference for non-chlorinated substrates. Members of the bacterial consortium were also characterized individually. All isolates were able to assimilate aniline. P. corrugata SB4 was able to grow on 4CA solely, while S. maltophilia SB5 was able to grow on 4-chlorocatechol. These results suggest that the degradation of 4CA in the presence of aniline by the bacterial consortium was a result of interspecies interactions