DE1643539C3 - Process for the microbiological production of D-pantoic acid from DL-pantoic acid - Google Patents

Description

The invention relates to a process for the microbiological production of D-pantoic acid from DL-pantoic acid by Be ^; fattening a culture medium containing DL-pantoic acid with a microorganism that is able to assimilate L-pantoic acid but is not able to assimilate D-pantoic acid. Incubation of the culture medium until L-pantoic acid in the medium is practically used up, and D-pantoic acid is obtained from the medium.

Since it is easily possible to convert the acids into their lactones and the lactones into acids Pantoic acid, pantolactone and their mixtures are equivalent to one another so that they are used in the present description and simply referred to as "pantoic acid" in the claim. D-pantoic acid, L-pantoic acid and DL-pantoic acid are hereinafter referred to as the D-isomer, the L-isomer for convenience and denotes the racemate.

D-pantoic acid is very important as an intermediate in the production of D-pantothenic acid.

The D-isomer has so far been most advantageous in practice by converting DL-pantolactone with quinine sulfate in a solution. Separation of the D-quinine pantoate thus formed by fractional crystallization and hydrolysis of the D-quinine pantoate. This procedure (hereinafter referred to as Quinine sulphate process called) is inevitable associated with disadvantages when it comes to large-scale manufacture is applied:

1) The procedure is quite complicated and cumbersome to carry out.

2) The D-isomer obtained in this process is not pure and always contains about 5% of the L-isomer contaminated, so that further cleaning is sometimes necessary is.

3) Quinine is very expensive and the manufacturing cost after this procedure change with the cost of quinine.

A new, easy to carry out process for the production of the pure D-isomer in the technical Scale is therefore desirable. Such a process, which is a simplification, leads to high yields and lowers the manufacturing cost is the subject of the invention.

The invention accordingly relates to a method for the microbiological production of D-pantoic acid from DL-pantoic acid. which is characterized in that a culture medium containing DL-pantoic acid with one of the microorganisms Brevibacterium inseptiphilium ATCC-21110, Brevibacterium malis ATCC-21111, Corynebacterium equi ATCC-21107, Corynebacterium humferium ATCC-21108, Arthrobacter tumescens ATCC-21109, Arthrobacter ureafaciens ATCC-21124 or Bacillus pulvifaciens ATCC-21112 inoculated, adjusted to a pH of about 5.0 to 10.0, and the Maintains temperature between about 15 and 50 ° C until the L-pantoic acid in the medium is practically consumed

In the quinine sulfate process, the racemate used as the starting material is treated with Purified quinine sulfate, while in the process according to the invention the crude racemate as starting material is used and there is no need to purify the starting material. Besides, that requires Process does not recover quinine, as is the case with the quinine sulfate process.

In general, natural forms of racemates are and are believed to be physiologically active

2 »by mikroorganismer! are consumed. Surprisingly, however, it was found that there were three Groups of microorganisms exist, classified according to their ability to assimilate pantoic acid be, namely group 1, which is the L-isomer, but

r> not assimilated the D-isomer, the group II, which the D isomers but not the L isomer assimilated, and Group III which has both the D isomer and the L-isomers assimilated. By using microorganisms of the first group, it is possible that

«Ι D-isomers to isolate from the racemate.

The microorganisms mentioned that are able to assimilate the L-isomer without adding the D-isomer assimilate are suitable for the purposes of the invention. You will be following the usual methods

π isolated, which is used to isolate microorganisms from Soil, sewage and air.

Contains a basal agar plate for isolation e.g. 0.1% urea, 0.1% potassium nitrate, 0.1%

ι »ammonium nitrate. 0.05% potassium dihydrogen phosphate. 0.05% dipotassium hydrogen phosphide. 0.05% magnesium sulfate. 0.01% yeast extract and agar (about 1.5 to 2.5%) in water. The main carbon source is about 0.5 to 4% of the D-isomer or L-isomer

π ßasalmcdium added. The two types of agar plates (i.e., the medium containing the D-isomcrc and the medium containing the L-isomcre) are mixed with the test organisms inoculated and incubated for a few days at 27 "C". The microorganisms assimilating the L isomer

".Ii ganismcn are selected from the microorganisms those on the plate containing the L-isomcrc, but not on the plate containing the D-isomcrc ability to grow.

Determining whether or not there is growth.

v> must be done with the necessary caution, as certain Microorganisms which the l.-Isomcre fail to assimilate able, on the plate containing the L-Isomcrc by assimilation of yeast extract and / or a small amount of impurities in the agar

mi can grow.

To isolate the microorganisms, for example, 0.1 g of a soil sample is added to 5 ml of DLA medium (see Table I) given in a test tube. The incubation takes place either stationary or under

tr> movement elwa I to 2 weeks. The media for the Isolation are described in Table 1. After appropriate dilution, a DLA agar plate with the Inoculate culture and incubate at 28 ° C for about 2 to 7 days.

The colonies formed are transferred to A, LA, DA and DLA agar slants and kept at 28 ° C. for 7 days incubated. The results are given in Table 2.

Furthermore, an eyelet with a 7-day culture is used Microorganism added to 5 ml of DLA, LA and SA medium (e.g. solution media) in test tubes and Incubated 5 days at 28 "C The amount of the remaining Carbon source, d. H. D- and L-pantoic acid, in the media is according to a standard analytical method The results are given in Table 3. The sign "+" here means "growth" and that Sign "-" "no growth".

Table 1 A medium

urea

KNO ₃

NH ₄ NO,

KH ₂ PO ₄

KjHPO ₄

MgSO ₄ · _{7H 2} O

Yeast extract

PH value

in tap water

LA agar plate

Plate of LA medium containing approximately 2-3% agar

DLA-Mer'ium 1% DL-pntoic acid or DL-pantolactone is added to the A-Mcdium and adjusts the pH to 7.0

0.1%

0.05%

0.05%

0.05%

0.05%

0.05%

0.01%

7.0 LA medium

Add 0.5% L-pantoic acid or L-pantolactone to the Α-medium and adjust the pH to 7.0 a

DA medium

Add 0.5% D-pantoic acid or D-pantoactone to the Α medium and adjust the pH to 7.0 a

A, LA and DA agar slants

Slanted tubes of A, LA and DA medium with about 2 to 3% agar

Table 2

Group strain no.

Growth on agar slant DLA LA DA

Trunk no. Growth aui Schrirgugar DLA LA DA LP 50-1 Y + + LP 54 + + - LP 265 S. f + - LP 27OS + + - LP 274 + + LP207S + + - LP I35S + + LP 26 S-2 + + - LP I4S + + - LP 49-1 + + - 210 + - + 205 + - + 362 B + - + 343 + - + 610 + - + 609 Λ 7 + - + 387 A-I + - + 678 Λ-3 + - + 678 A-5 + - + 468 + + + 171 + + +

LP 216-1 LP 166-3 LP 208 LP 75-1 LP 75-2 LP 106-2 LP 46 S LP 60S LP I66F LP l-ll

533
538
539
545
553
603
620
571
628

671
324

Table 3 1643 539 6th Medium,% 5 Group strain no. Amount of coal THERE IFO number Rest 100 1 LP 216-1 medium LA 100 LP 166-3 DLA 0 100 LP 208 12402 50 0 100 LP 75-1 12403 50 0 100 LP 75-2 12404 50 0 100 LP 106-2 12405 50 0 100 LP 46 S 12406 50 0 100 LP 60 S 12407 50 0 100 LP 166F 12408 50 0 100 LP 1-11 12409 50 0 iOO LP5O-1Y 12410 50 0 100 LP 54 12411 50 20th 100 LP 265 S. 12412 65 0 100 LP 270S 12413 60 0 100 LP 274 12414 50 0 100 LP 207 S. 12415 55 0 100 LP 135S 12416 55 0 100 LP 26 S-2 12417 50 5 100 LP 14 p 12418 60 20th 100 LP 49-1 12419 75 20th 0 2 533 12420 70 35 0 538 12421 80 100 0 539 50 100 0 545 50 100 0 553 50 100 0 603 50 100 0 620 50 100 0 571 50 100 0 628 50 100 5 210 50 100 5 205 50 100 5 362 B 50 100 5 343 55 100 0 609 A-7 55 100 0 387 A-I 55 100 0 678 A-3 50 100 0 678 A-5 50 100 75 "671 50 100 60 324 50 80 80 468 70 60 60 171 55 90 80 70 45

Analysis error ± 10%.

The strains of microorganisms obtained in this way are:

Corynebacterium equi Ip-I-II (ATCC-21107), Corynebacteriu r. humiferum 1 p-106-2

(ATCC-21108),
Arthrobacteriumescens lp-75-1 (ATCC-21109),

Arthrobacterurea faciens lp-135-S

(ATCC-: ti 24), _b5 Brevibacterium insectiphilium I p-14-S

(ATCC-21110),

Brevibacterium malis Ip-166-3 (ATCC-21111), Bacillus pulvifaciens LP-60-S (ATCC-21112).

Some of the laxonomic characteristics of these microorganisms differ from those in Bergey's manual of Determinative Bacteriology, Seventh edition ", but

their main characteristics agree with the literature. The morphological and physiological Features are given in Table 4 below.

Table 4

Taxonomic description Arthritis Arthritis Brevi Brcvi Bacillus Coryne- C'orync- bacter hacler hacterium bacterium pulvifacicns hacterium bacterium tumescens ureafaciens insectiphilium malis equi humiferum Mute no. lp-75-1 lp-135-.S lp-14-S Ip-166-3 lp-60-S Ip-I-Il Ip-I06-2 Cocci up Cocci up Kuiv sticks Cocci up rod Tiixonomic c Cocci up Cocci up rod rod rod King sound rod rod 0.4 to 0.6 to 0.8 to 0.5 to 0.4 to Shape of cells 0.5 x 0.5 to 0.5 to 0.6 x 0.7 to 0.8 x 0.8 to 1.0 x 1.5 to 0.6 x 0.6 to 0.6 x 3 to 0.7 x 0.7 to 3 μ 2.5 µ 3 μ 1.2 μ 8 μ 5 μ pleomorphic branched. pleomorphic pleomorphic pleomorphic pleomorphic pleomorphic immobile immobile immobile immobile movable agility immobile immobile no no no no available Scourges no no no no no no ellipsoid, Spore formation no no

Gram stain

Oxygen demand
Growth temperature

Agar slant

Agar plate

Potato sloping culture

positive

(14 hours)

changeable

(4 days)

aerobic

good

growth

at 25-37 C.

no

growth

thread-like,
opaque, cream-colored,
glittering

circular.

1-1 .. 'mm

Diameter.

closed

increased, white,

opalescent,

wet

growth
very good,
cream colored,
wet
glittering

positive
(14 hours
Days)

aerobic
good
growth
at 25 C, no
growth
at 7 C "or

thread-like,
opaque,
glittering,
white damp

circular,
less than
0.5 mm
Diameter,
auricular,
umbilical,
opaque, dry,
White

good growth, yellowish brown,
dry

positive
(14 hours
4 days)

aerobic

good

growth

at 20-37 C.

no

growth

Κί »ϊ 7 C r \ Ac * T

48 C

thread-like, opaque, cream-colored,
shiny, damp
circular with a diameter of 0.5-2 mm, closed, raised, opalescent, white to cream-colored

cream-colored, strong moist growth,

shiny pale yellow,

dry

positive
(14 hours)
changeable
(4 days)

aerobic
growth
at 7-25 C ",
no

growth
at 37 C

thread-like,
opaque, yellow,
glittering
wet

circular
with 1.5 mm
Diameter,
closed,
raised, yellow,
moist, opaque

positive
(14 hours
Days)

aerobic

good

growth

at 7-25 C,

weak

growth

κ »; π r t »in

growth
at 48 C.
thread-like,
opaque, yellow,
glittering
wet

circular
with 0.5-1 mm
Diameter,
closed,
raised, yellow,
opaque, moist

positive
(14 hours)
changeable
(4 days)

aerobic
growth
at 25-37 C,
no

growth
at 7 C or
H"; .is r

strong
Growth,
pale yellow,
dry

thread-like,
opaque, cream-colored,
glittering
wet

circular
with

0.7-2.5 mm
Diameter,
closed,
raised, pale yellow, moist,
opaque

weak
growth

0.7-1.0 x

1.0-1.5 µ

Sporangia

swollen

positive

(14 hours)

changeable

(5 days)

aerobic

good

growth

at 23-48 C.

no

growth

h »i 7 Γ

thread-like, opalescent, white, shiny moist

circular with

0.2-1.5 mm diameter knife, closed, pale yellow, moist, opalescent

Growth, pale yellow

Litmus milk is not alkaline

change

Acid formation from none
Carbohydrate

no

no
change

no

alkaline

Acid formation
from sucrose

easy
alkaline,
curdled,
Peptonization

No acid formation
from sucrose

no
change

no
change

no

9 description 1643 539 Brevi IO Bacillus I Coryne- bacterium pulvifaciens *
1 continuation Taxonomic bacterium insecliphilium Coryne- humiferum Brevi lp-60-S ■ bacterium Arlhro Arthritis lp-14-S bacterium no equi lp-106-2 bacler bacter no malis Trunk no. no tumescens ureafaciens liquefaction Ip-I-Il liquefaction I p-166-3 (gradually!) positive no lp-75-l Ip-13S-S positive no Nile formation liquefaction positive no positive from Nilral liquefaction no no positive (ielatine- no liquefaction positive liquefaction no Siichkultur no positive liquefaction no no no llulrolysis of npin no positive no strength positive no positive positive HjS education η ι ¹ 1 η positive positive positive no no ΙηιΙηΙΚίΙίΙιιησ no positive n.'tn "..." no no Voges-Proskauer- no no no no Responsiveness positive no positive KiiUilase formation no no positive positive no Cellul.ise- no no positive Education no positive no Assimilation positive no no by D-Pantoin- - acid positive - positive Assimilation positive positive positive good by L-Pantoin- growth acid c strong Assimilation positive positive of citrate l% igcs Glucoscagar Soybean agar

For the large-scale production of the D-isomer by the the L-isomer assimilating microorganisms according to the invention, it is expedient to use a liquid Use culture medium / u. The cultivation is generally stationary or in shaking culture or Submerged culture carried out.

The medium usually contains the racemate as the main carbon source. As carbon sources you can use in addition to the L. isomer, for example, glucose. Sucrose. Dextrin, starch, glycerin, or sorbitol alone or to be used in groups.

Organic nitrogenous materials, for example, are suitable as a source of usable nitrogen, like urea. Peptone, meat extract. Casein. Edamin. Casein hydrolyzate, soybean meal, corn steep liquor. Yeast, yeast extract, and inorganic nitrogen compounds, such as ammonium nitrate, ammonium chloride, ammonium phosphate. Ammonium sulfate and sodium nitrate.

In general, other organic salts are added (e.g. potassium monohydrogen phosphate, sodium chloride or magnesium sulfate) and vitamins (e.g. thiamine, nicotinic acid, biotin, p-aminobenzoic acid, Pyridoxine) required for good growth.

The racemate used as starting material can be in the form of salts, e.g. B. of sodium salts, potassium salts, Calcium salts or ammonium salts can be used. These salts are appropriate to the medium added in an amount greater than 0.5%. The usual concentration in the medium varies depending on the Culture conditions of about 1 to 30%. The starting racemat is before cultivation all at once or

Growth

added intermittently in several portions or continuously during cultivation.

The starting material is in the form of the free acid or salt, e.g. B. the sodium salt, potassium salt or calcium salt, or in the form of the lactone powder. optionally after prior dissolution or emulsification in water.

For cultivation, the pH of the culture medium is adjusted to about 5.0 to about 10.0. conveniently set to b.5 to 8.5 and, advantageously maintaining the cultivation temperature to elwa 15 to 50 ⁰ C to 25 to 35 C. Ventilation is essential for growth. Suitable antifoam agents are expediently used.

Cultivation is continued until the 1st isomer is practically consumed in the medium. The cultivation time is different depending on certain Factors e.g. B. microorganism, temperature. Ventilation, movement and composition of the medium.

It is also possible to degrade the L-isomer in an aqueous solution by combining it with enzymes extracted from the cells of the microorganisms. The desired D-isomer remains unchanged in the medium.

The D-isomer is separated off by simple, customary methods, e.g. B. by adsorption chromatography on activated carbon or alumina or by partition chromatography with one with water immiscible solvents such as ethyl ether, benzene and chloroform or ethyl acetate or by distillation. These methods can be used alone or in combination.

In the following examples, the yields are based on the D-sodium pantoate in the starting materials calculated. The percentages in Table 3 and the yields in the examples relate on weight / poem and in all other cases on weight / volume. Those with the strains of the microorganisms The ATCC numbers given are the depository numbers of the microorganisms at American Type Culture Collection, Maryland. UNITED STATES.

100 ml

"ice cream Sodium Dl.l pi el 1 Lin 200-1 ml-Erlenmeyer Urea. Piston, dei Nutrient solution KNO ₁ . 7.9% NH.Nn, 'antoat. 0.2% MgSO ₄ ■ '7 Η. 0.1% KH ₂ PO ₄ , 0.1 "/ η K ₂ HPO ₄ . 0.05% Yeast extract O. 0.05% 0.05% 0.1%

was sterilized by autoclaving and after Cooling with a suspension of Brevibacterium malis Ip I66-3 (ATCC-21111) inoculated by rinsing an agar slant with physiological saline solution.

The preculture was shaken at 28X for 3 days incubated, whereupon 1 ml of the culture in five 200 ml fermentation flasks was revaccinated, each containing 100 ml of the same nutrient solution. These flasks were used for 4 days Shaken 28 ° C. The combined culture filtrate from all flasks was adjusted to pH I and repeated with Ethyl acetate extracted after taking the remaining D-pantoic acid in the filtrate by autoclaving had been lactonized at a pressure of 1.177 bar for a period of 10 minutes. The solvent was distilled off and the residue obtained was purified by further distillation and condensation. Here were 2.5 g (yield · 83 "/») D-pantolactone as wciUe needles received.

Melting point 91 to 92 "C
[λ] -50.5 "(H ₂ O)
NMR: (iPP ^m (in CDCI ₂ )

1.08 (CH,) 1.22 (CH ₁ )

4.00 (CH ₂₎ 4,07.4,20 (CHOH)

Example 2

A 200 ml Erlenmeyer flask was sterilized. which contained 100 ml of a nutrient solution containing 5.24% DL-nalrium pantoate removed, and then vaccinated with one Suspension of Brevibacterium insectiphilium lp-14-S (ATCC-21110) obtained by rinsing a slant culture with physiological saline solution. The preculture was shaken for 3 days at 28 ° C and then inoculated with 1 ml of the culture five 200 ml fermentation flasks, each containing 100 ml of the same nutrient solution. The flasks were shaken for 4 days at 28 ° C. combined culture filtrate of all flasks to pH 1 and extracted the filtrate repeatedly with ethyl acetate after the remaining D-pantoic acid in the filtrate had been iactonized by autoclaving under a pressure of 1.177 bar for a period of 10 minutes.

The solvent was distilled off and the residue obtained by further distillation and Condensation cleaned. 1.76 g (yield 88%) of D-pantolactone were obtained as white needles.

Optical rotation [λ] 50.7 ° (H ₂ O)

Example 3

A 200 ml Erlenmeyer flask containing 100 ml of the the same nutrient solution as in Example 2 was sterilized and then with a suspension of Arthrobacter tumescens Ip 75-1 (ATCC-21109) inoculated, obtained by rinsing an agar slant with physiological saline.

The culture was agitated i days at TSC, to which 1 ml of the culture in five 200 ml Gärkolben was unigeimpft, which contained the same nutrient solution. The flasks were shaken at 28 "C for 4 positions.

The combined coolant micrat of all flasks was on pH I adjusted and extracted repeatedly with ethyl acetate after the remaining D-pantoic acid in the

I ^: i) tr; it rjijri'h Λιιΐοΐί j: »vi ^ rijn ijnlpr elnCül Dflick VOH

1,177 bar for a period of 10 minutes lactonisieri had been. The solvent was removed and the residue obtained is purified by further distillation and condensation. 1.81g (yield 90%) D-pantolactone obtained as white needles which have an optical rotation [λ] of -50.4'C (Η.Ό) had.

Example 4

Hin 200 ml Hrlenmeyer flask. the K) OmI the the same nutrient solution as in Example 2 was sterilized and then with a suspension of Arthrobacter ureafaciens Ipl35-S (ATCC-21124) obtained by rinsing an agar slant with physiological saline. the Preculture was shaken for 2 days at 28'C, whereupon I ml of the culture in five 200 ml fermentation flasks. containing the same nutrient solution was inoculated. The pistons were shaken at 28 ° C for 4 days.

The combined culture filtrate from all flasks was adjusted to pH I and repeated with ethyl acetate extracted after the remaining D-pantoic acid im The filtrate was lactonized by autoclaving under a pressure of 1,177 bar for a period of 10 minutes had been. The solvent was distilled off and the residue obtained by further distillation and Condensation cleaned.

This gave 1.64 g (yield 85%) of D-pantolactone as white needles which _{showed an optical rotation [, \] = -50.6 "C (H 2} O).

Example 5

A 200 ml Erlcnmeyer flask containing 100 ml of the the same nutrient solution as in Example 2 was sterilized and then with a suspension of Corynebacterium equi Ip 1-11 (ATCC-21107) vaccinated, obtained by rinsing an agar slant with physiological saline. The preculture was shaken for 2 days at 28 ° C, whereupon 1 ml of the culture in five 200 ml fermentation flasks containing the same Containing nutrient solution, was vaccinated. The flasks were shaken at 28 ° C for 4 days.

The combined culture filtrate from all flasks was adjusted to pH 1 and repeated with ethyl acetate extracted after the remaining D-pantoic acid in the filtrate by autoclaving under a pressure of 1.177 bar lactonized for a period of 10 minutes had been. The solvent was distilled off and the residue obtained by further distillation and Condensation cleaned. 1.71 g (ex

yield 85%) of D-pantolactone was obtained as white needles, which hold an optical rotation [x] = -50.6 ⁰ C (H ₂ O).

Example 6

A 200 ml Erlenmeyer flask containing 100 ml of a Nutrient solution containing the same composition as in Example 2 was sterilized and then with a Suspension of Corynebacterium humiferum Ip 106-2 (ATCC-21108). that by rinsing an agar slant with physiological saline solution. The preculture was 2 days at 28 "C" shaken. whereupon I ml of the culture in five 200 ml fermentation flasks. containing the same nutrient solution was inoculated. The flasks were at 28X for 4 days shaken.

The combined culture filtrate of all flasks was adjusted to pH 1 and repeatedly extracted with ethyl acetate after the remaining D-pantoic acid in the filtrate had been ionized by autoclaving under a pressure of 1.177 bar for a period of 10 minutes . The solvent was distilled off and the residue obtained was purified by further distillation and condensation. Here, 0.87 g (yield 85%) of D-pantolactone was obtained as white needles, which had an optical rotation [α] · of -50.4 ⁰ C (H ₂ O).

Example 8

A 200 ml Erlenmeyer flask. the 100 ml the containing the same nutrient solution as in Example 1, was sterilized and then with a suspension of Brevibacterium maliz Ip 166-3 (ATCC-21111) vaccinated, by rinsing an agar slant culture with physiological

WHULIIIUIt

extracted after the remaining D-pantoic acid in the filtrate had been lactonized by autoclaving under a pressure of 1,177 bar for a period of 10 minutes. The solvent was distilled off and the residue obtained was purified by further distillation and condensation. Here, 1.69 g (yield 84%) of D-pantolactone was obtained as white needles, an optical rotation [dt] of ^r -50.7 C; had (H O).

Example 7

A 200 ml Erlenmeyer flask containing 100 ml of a Nutrient solution containing 2.62% DL sodium pantoate was sterilized and then with a suspension from Bacillus pulvifaciens lp60-S (ATCC-21112) obtained by rinsing an agar slant with physiological saline. the Preculture was shaken for 2 days at 28 ° C, after which 1 ml of the culture in five 200 ml fermentation flasks, all of which contained the same nutrient solution, was vaccinated. The flasks were shaken at 28 ° C for 4 days.

The combined culture filtrate from all flasks was shaken for 2 days at 28 ° C, after which the entire Culture was transferred into a standard 2-liter fermenter, which is equipped with a device for moving the fermenter, a vent, a temperature control device, a pH analyzer, etc. was provided and I I contained the same nutrient solution. The culture was at 28 ° C with aeration and agitation incubated. After a cultivation time of 32 hours, 53 g of sodium DL pantoate became the medium given. At this point in time the L-panioic acid in the starting medium was practically consumed. the Cultivation was continued for about 30 hours.

The culture filtrate was adjusted to pH 1 and extracted repeatedly with ethyl acetate after the remaining D-pantoic acid in the filtrate had been lactonized by autoclaving under a pressure of 1.177 bar for a period of 10 minutes. The solvent was distilled off and the residue obtained was purified by further distillation and condensation. In this way, 86 g of D ^u antolactone (yield 86%) were obtained as white needles, which have an optical rotation [α]
of -50.6 ° C (H ₂ O).

Claims (1)

Claim: Process for the microbiological production of D-pantoic acid from DL-pantoic acid, characterized in that a culture medium containing DL-pantoic acid is mixed with one of the microorganism strains Brevibacterium insectiphilium ATCC-21110, Brevibacterium malis ATCC-21111, Corynebacterium equi ATCC-21107-, Ciferiumnebacterium ATCC 21108, Arthrobacter tumescens ATCC 21109, Arthrobacter ureafaciens ATCC 21124 or Bacillus pulvifaciens ATCC-21112 was inoculated to a pH value of etv / a 5.0 adjusted to 10.0, and the temperature is between about 15 and 50 ⁰ C holds until the L-pantoic acid in the medium is practically consumed