Patent stm,<v 689

T~U( o . e o ~ ; .

Fig. 2. Chromatogram of tryptic digest undcr gradient conditions.

by first bringing racemic lysine into contact with a culture or a treated culture of a microorganism, and then collecting and isolating the D-lysine from the reaction mixture.

The microorganisms the inventors used during laboratory tests they carried out comprise bacteria such as Achromobacter delman,ae IAM 1457 (FERM BP-5290), Escherichia coli ATCC 11303 and ATCC 11105, yeasts such as those belonging to Yarrowia, Candida or Apiotrichum and molds of the Penicillium group.

Fig. 3.

I .J

METHANE ' i ~ ~ A T I O N O F ~

Flow scheme of Kobayashi's et al. invcntion.

4000

350O

3O00

2500

REACTION TF.IIIPE]MTUR[: 55"C SEED SUJOGE: 0 DIGESTED SLUDGE

FROM NIGWI" SOIL TREATMENT PLAll7

A HIGH TEMPERATURE DIGESTED SLUI~ $[WA~ TI~TMElff PtJUff

R[ICTION CAPACITY: 2750

: JUDOITION OF $11BSTRATE

O A : 7.5! O A : 19..50

PROPERTY OF RAW SLUOG(

1 OmJD co~a~ wox

0 I 2 3 4 5 I; 7 8 9 I0 II 12 13 14 15 IG

OP[RATIOII PERIO0 (DAY)

Fig. 4. Relation between the operation period and the cumulative gas yield.

Quantification of an optical isomer of lysine was carried out by high perform- ance liquid chromatography.

As a typical example of their labora- tory tests the following will be described.

Into a shaking tlasks having a volume of 500ml was charged I()(Iml of a medium (pH 7.(I) comprising 2% of DL-Iysinc monohydrnchloride, (1"2% of ammonium sulfate, 0.1c5~ of potassium dihydrogen phosphate, (1.05c)~ of mag- nesium sulfate and ().02C/~, of a yeast extract, and thc medium was sterilized at 120°C for 10 min. A Ioopful of Yar- rowia lipolytica IFO 1209 was inocu- latcd into the medium, and cultured at 30°C for 168 h with shaking. Thc cell wits removed by centrifuging 10(}0 ml of the above culturc broth to obtain a supernatant. After the supernatant was ajusted to pH 6-0 with hydrochloric acid, ultra-filtration was carried out in order to remove protein and others, whereby a filtrate was obtained. After activaled carbon was added to the Ill- Irate to effect decolorization, the lil- trate was concentrated under reduced pressurc, and 20(Iml of ethanol was added to 20g of the concentrate to obtain 5 '8g of t)-Iysine monohy- drochloridc as crude crystals. 5"8 ml of water was addcd to the crude ciTstals, and the crude crystals were dissolved by heating, and then recrystallizcd by cooling to obtain 2 .t) g of crystals of D-lysinc monohvdrochloridc.

Optical roation: [~1~': - 20.9 "~ (( '=S.6x H('I)

Optical purity: lI)0~i

5 pages. 12 claims.

Referem'es US patent publication 3,527,776. International patent publication WO 92/10579. Japanese patent publication JP-A 592108q4.

A method of anaerobic digestion of sewage sludge

(US pawnt application 5-335551 to Hitachi Zosen Coq~oration, Osaka, Japan, corresponding to US patent 5. 723, 048)

Biochemists Y. Kobayashi and M. Akita, both working on behalf of the above company, developed a method of treating sewage sludge, wherein thc sewage sludge containing a large quan- tity of surplus sludge is subjected to preliminary heat treatment, and then the heat-treated sludge is dewatercd to permit a nitrogenous componcnt to bc

690 Patent survey

transferred to eliminated water whereby the nitrogenous component in the dewatered sludge can be reduced. The resulting dewatered sludge can stably undergo methane fermentation even at a high concentration of 10-25% by weight.

Figure 3 is a flow scheme of the system involved.

Surplus sludge of 5% containing about 70% VTS was subjected to heat treatment at 150°C for 1 h. The heat- treated sludge was subjected to centri- fugal dewatering to give 15% dewatered sludge. On the other hand, 4% initial settling sludge containing about 87% VTS was subjected to sterilizing treat- ment at about 120°C and then to centri-

fugal dewatering to give 15% dewatering sludge. The 15% dewatered sludge from the surplus sludge was combined with the 15% dewatered sludge from the initial settling sludge in the ratio of 4 (surplus):6 (initial settling) and the resulting dewatered sludge was transferred to a mixing vessel. A part of digested sludge was taken out from the undermentioned methane fermentation vessel of dewa- tered sludge and recycles to the mixing vessel. The digested sludge taken out was mixed with the above dewatered sludge there. The resulting mixture was supplied to the methane fermentation vessel of dewatered sludge. On the other hand, the digested sludge whose

amount is equal to that of dewatered sludge supplied to the methane fer- mentation vessel of dewatered sludge was taken out from the fermentation vessel.

Figure 4 is a graph showing relations between the operation period and the cumulative gas yield in case the sludge is treated according to the digestion method described above.

15 pages, 11 figures, 8 claims.

References 9 US patent publications. 4 Japanese patent publications.