摘要:
The invention relates to a nucleotide sequence coding for the mannitol 2-dehydrogenase and a method for producing D-mannitol. Previously known biocatalytic methods for producing D-mannitol yield only small production rates due to the small number of specific activities of mannitol 2-dehydrogenases used for transforming D-fructose into D-mannitol. D-mannitol production can be improved by supplying a nucleotide sequence which codes for a mannitol 2-dehydrogenase having a higher specific activity. Mannitol production can be increased in a particular manner by creating a regeneration system for reduction equivalents by introducing and/or strengthening a formiate dehydrogenase in a microorganism.
摘要:
Optically active enantiomers of alkyl .alpha.-phenoxypropionates, and of derivatives thereof, can be racemized in good yields and without formation of decomposition products with the aid of an alkali metal (C.sub.1 -C.sub.5) alcoholate, an alkali metal hydroquinone, an alkali metal phenolate or an alkali metal hydroxyphenoxypropionate, or derivatives thereof.
摘要:
The present invention relates to glucose- and sophorose-lipids of the formula I ##STR1## in which R.sup.4 is --OH or a group of the formula II, ##STR2## n is an integer from 2 to 26, R.sup.1 and R.sup.2 are, independently of one another, H or ##STR3## R.sup.3 is H or --OH in the case where R.sup.4 is --OH, and is H or --OH or a group of the formula III, ##STR4## in the case where R.sup.4 is a group of the formula II, to a process for obtaining them by fermentation, and to their use as surfactants.
摘要:
Bacterial strains are capable of the formation of rhamnolipids, which they generate in the culture solution. If bacteria of the type Pseudomonas aeruginosa are employed for the fermentation, these microorganisms synthesize rhamnolipids in a concentration of 70-120 g/l of culture solution. The L-rhamnose can be recovered directly from the culture solution by hydrolysis of the rhamnolipids, i.e. without a complicated separation of the cell material and without isolation of the rhamnolipids before hydrolysis.
摘要:
A process for reacting substrates with biocatalysts in a two-phase liquid system disposed in a columnar vessel having a top portion with an exit opening and a first filter disposed therein, a bottom portion with an entrance opening and a second filter disposed therein, a feed line connecting the exit and entrance openings, and a pump disposed in the feed line. The process comprises the steps of: stirring the two-phase liquid in the columnar vessel to accelerate sedimentation and minimize accumulation of the biocatalysts in the top portion of the vessel; selectively controlling the temperature of the two-phase liquid within the vessel; drawing, with the pump, a portion of the two-phase liquid through the exit opening and first filter; and passing the drawn-off portion of the two-phase liquid through the feed line and through the entrance opening and second filter into the vessel to enhance miscibility of the individual phases of the two-phase liquid with the vessel.
摘要:
Litter for cats and small animals often consists of a mixture from dried material of plant origin and an adjuvant that promotes agglomeration when the mixture is exposed to moisture. The invention relates to a novel litter that is characterized in that the dried material of plant origin is present in a particle size range in which the diameters of 80% of the particles, based on the mass, range from more than 0 μm to less than 1000 μm. The mass sum distribution of the particle size distribution, at least in the range between 50 μm and 1000 μm, is larger than an integrated statistical Gaussian distribution at which the Gaussian distribution is a normal Gaussian distribution with an average value of 100 μm and a standard deviation of 800 μm and at which the particle size distribution deviates by more than 10% from this statistic Gaussian distribution.
摘要:
The invention relates to sophoroselipids of formula (I) wherein R4 represents H, —CH2CH3, —CH2CH2CH3, n is an integer number from 2 to 27, R1 and R2 represent, independently from each other, H or a group of formula (II), and R3 represents H or —OH. The invention also relates to a method for producing sophoroselipids of formula (I) wherein R1, R2, R3 and n have the aforementioned meanings and R4 represents —CH3, —CH2CH3 or —CH2CH2CH3. According to this method, a yeast capable of secreting a sophoroselipid in the form of a lactone in the culture excess, is fermented in a culture medium containing a glycerin. a succinate, a mono-, di- and/or tri-saccharide and a lipid precursor, said sophoroslipid being then isolated from the culture solution. The inventive method is characterised in that the lipid precursor contains one or more 3-alkanols, 4-alkanols or an alkanone with a chain length from 6 to 30 carbon atoms or mixtures of said alkanoistalkanone. Furthermore, according to a variant of the aforementioned method for producing sophoroselipids of formula (I), wherein R1, R2, R3 and n have the meanings aforementioned and R4 represents —CH3, —CH2CH3 or —CH2CH2CH3, the culture medium is maintained during fermentation under a reduced oxygen concentration. The new sophoroselipids may be used, e.g., as surfactants, cosmetics, disinfecting agents or pharmaceutical products.
摘要:
Pseudomonas aeruginosa and its use in a process for the biotechnological production of L-rhamnoseBacterial strains are capable of the formation of rhamnolipids, which they generate in the culture solution. If bacteria of the type Pseudomonas aeruginosa are employed for the fermentation, these microorganisms synthesize rhamnolipids in a concentration of 70-120 g/l of culture solution. The L-rhamnose can be recovered directly from the culture solution by hydrolysis of the rhamnolipids, i.e. without a complicated separation of the cell material and without isolation of the rhamnolipids before hydrolysis.
摘要:
The invention relates to .alpha.-L-rhamnosidase, which catalyzes the cleavage of the bond between terminal rhamnose and the aglycone of rhamnose-containing glycosides, a process for preparing it by biotechnological means, and its use for preparing L(+)-rhamnose (6-deoxy-L-mannose).
摘要:
Resolution of the racemates of phosphorus-containing functional acetic acid derivatives can be carried out in high yield and in enantiomeric purity using hydrolases such as esterases and lipases.