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一、菌名:Alcaligenes xylosoxydans

 二、分類地位:

Alcaligenes是alkali-producing,也就是產鹼的意思。

xylosoxydans其中的xylose→ wood sugar，而oxydans→oxidizing，合起來就是oxidizing xylose，也就是氧化木糖。由於Achromobacter 跟Alcaligenes這兩個屬的特性非常相似，先前被命名Achromobacter xylosoxidans，之後被分類為Alcaligenes denitrificans subsp. xylosoxydans。全名為木糖氧化產鹼菌。

Alcaligenes有兩個種，即A.facalis和A.denitrificans，後者又分两個亞種，即去硝化亞種（A.denitrfuans subsp. denitrfuans）和木糖氧化亞種（A. denitrfuans subsp. xylosoxydans）。

三、自然界棲息地:

生長範圍很廣，在土壤或水中都可以發現他們的存在。大部分從臨床樣本分離出來，例如血液、唾液、傷口、膿、尿糞便。它特別的敗血病的導因是在醫院的醫療設備上。此外也會在小孩和有囊胞性纖維症而導致肺病惡化的病人的呼吸道發現。

 四、大小，形態：

桿狀，周圍有邊毛，具移動性。直徑為0.5到1.0μm，長度為0.5到2.6μm，通常為單獨出現而非菌落。為革蘭氏陰性菌，絕對好氧菌。菌落在nitrient agar為無色。DNA的mol%G+C是66.0~69.8。

Alcaligenes xylosoxydans

http://vietsciences.free.fr/khaocuu/nguyenlandung/cacnhomvikhuanchuyeu3.htm

五、適合生長環境：

１．適合生長溫度：20℃~30℃

２．理想pH值：7.0     

３．氧氣需求：絕對好氧（以氧當電子接受者）

六、培養特性：

一般傳統的培養基都可以培養。想要特別把它獨立出來培養可以用下列：

 七、生化特性：

可利用L-malate，succinate,，adipate，meso-tartrate，itaconate當作carbon來源。

 八、致病性或應用:

致病性:

Alcaligenes xylosoxidans感染引起之新生兒腦膜炎則極為罕見。臨床上此菌主要來自水源污染，且幾乎對所有抗生素都具有抗藥性，感染此菌的新生兒腦膜炎死亡率極高。

本例為一六天大足月男嬰，以發燒、全身抽搐 等症狀來求診，根據腦脊髓液培養出A.xylosoxidans及藥物敏感試驗而給與用 Imipenem + TMP-SMZ治療28天而有顯著進步。

但因病嬰經一連串腦部超音波及電腦斷層檢查發現腦室有逐漸擴大的趨勢，故於三個月大時接受 腦室－腹腔引流術治療，情況良好。

但因連續ABR (聽力腦幹反應)追蹤複查發現有嚴重聽力障礙，故於九個月大時裝上兩側助聽器，並繼續於門診追蹤複查 。

應用:

應用於畜牧廢水中氮的去除，其目的在於提升廢水中氮碳去除功能以及降低處理成本。

同時硝化脫硝之異營硝化菌的應用，可以單槽進行硝化及脫硝反應，直接將TKN及NH3轉化為氮氣，可省簡化傳統除氮單元之設置，又因脫硝產生鹼度可以中和硝化所產生的酸度，而減少了廢水pH的變化幅度，同時硝化脫硝反應所消耗的碳源部分來自廢水中之COD，可達成同時去除氮及COD之功能，減少外加碳源所增加之成本。

異營硝化菌亦可單純當作生物製劑應用在COD濃度高而硝化效率低的硝化槽，應可提高硝化效率及COD之去除效率。

另外，對於異營性硝化作用之機制與特性，以及其於反應槽內隨時間空間之分佈等問題若能加以進一步的探索，相信對於增進傳統除氮系統效率之研究必然有很大的助益。

  九、參考文獻:

1.     http://www.vghtpe.gov.tw/~jcma/5704/570412_c.htm

2.     http://www.ncu.edu.tw/~ls/chinese/menu_title/faculty/whole_time_faculty/SLH/SLHc.htm

3.     http://myweb.scu.edu.tw/~93134046/introduce.html

4.     Bergey’s manual of Systematic Bacteriology P361~373

5.     http://vietsciences.free.fr/khaocuu/nguyenlandung/cacnhomvikhuanchuyeu3.htm

1.Production of Alcaligenes xylosoxydans EMS33 in a Bench-scale Fermenter

Optimization of medium composition and pH for chitinase production by the Alcaligenes xylosoxydans mutant EMS33 was carried out in the present study and the optimized medium composition and conditions were evaluated in a fermenter. The medium components screened initially using Plackett-Burman design were (NH sub(4)) sub(2)SO sub(4), MgSO sub(4) 7H sub(2)O, KH sub(2)PO sub(4), yeast extract, Tween 20 and chitin in shake flask experiments. The significant medium components identified by the Plackett-Burman method were MgSO sub(4) 7H sub(2)O, Tween 20 and chitin. Central composite response surface methodology was applied to further optimize chitinase production. The optimized values of MgSO sub(4) 7H sub(2)O, Tween 20, chitin and pH were found to be 0.6 g/l, 0.05 g/l, 11.5 g/l and 8.0, respectively. Chitinase and biomass production of Alcaligenes xylosoxydans EMS33, was studied in a 2-l fermenter containing (g/l): chitin, 11.5; yeast extract, 0.5; (NH sub(4)) sub(2)SO sub(4), 1; MgSO sub(4) 7H sub(2)O, 0.6; KH sub(2)PO sub(4), 1.36 and Tween 20, 0.05. The highest chitinase production was 54 units/ml at 60 h and pH 8.0 when the dissolved O sub(2) concentration was 60%, whereas the highest biomass production was achieved at 36 h and pH 7.5 without any dissolved O sub(2) control

2.Site-directed mutagenesis alters DnaK-dependent folding process

The overproduction of d-aminoacylase (A6-d-ANase) of Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) is accompanied by aggregation of the overproduced protein, and its soluble expression is facilitated by the coexpression of DnaK-DnaJ-GrpE (DnaKJE). When the A6-d-ANase gene was expressed in the Escherichia coli dnaK mutant dnaK756, little activity was observed in the soluble fraction, and it was restored by the coexpression of DnaKJE or the substitution of the R354 residue of A6-d-ANase for lysine. These results suggest that the guanidino group of the R354 residue of A6-d-ANase disturbs its proper folding in the absence of DnaK and the disturbance is eliminated by binding of DnaK to the R354 residue in the presence of DnaK. This is the first report that the DnaK-dependent folding process of the enzyme is altered by site-directed mutagenesis

3.Antibacterial effects of knotwood extractives on paper mill bacteria

Hydrophilic knotwood extracts from 18 wood species were assessed in disc diffusion and liquid culture tests for antibacterial effects against three species of paper mill bacteria. The Pinus sylvestris, P. resinosa, P. contorta, and P. banksiana extracts decreased or inhibited bacterial growth. The susceptibility order was P. sylvestris > P. resinosa > P. contorta > P. banksiana, correlating with the concentrations of pinosylvin and pinosylvin monomethyl ether in these wood species. Also, Pseudotsuga menziesii and Thuja occidentalis extracts had a small inhibitory effect. The Gram-positive Bacillus coagulans was more susceptible to the extracts than the Gram-negative Burkholderia multivorans and Alcaligenes xylosoxydans. The main components in the Pinus knotwood extracts were pinosylvin monomethyl ether and pinosylvin, suggesting these to be the active components. Therefore, pure pinosylvin, pinosylvin monomethyl ether, and dihydro-pinosylvin monomethyl ether were also tested. All compounds showed antibacterial effects. However, higher concentrations were needed for these pure compounds than for the knotwood extracts. Pinosylvin had stronger antibacterial effects than pinosylvin monomethyl ether. This work shows that knotwood extracts, especially from Pinus species, have a potential for use as natural biocides in papermaking

4.Purification and characterization of chitinase from Alcaligenes xylosoxydans

Extracellular chitinase from Alcaligenes xylosoxydans was purified to electrophoretic homogeneity using affinity and gel filtration chromatography. The molecular mass of chitinase was estimated to be 45 kDa and 44 kDa by SDS-PAGE and gel-filtration, respectively. The enzyme was optimally active at 50 degree C (over 30 min) and pH 5. Activity staining after PAGE showed a single band. The Km for chitin was 3 g l super(-1). Cu super(2+) and Na super(+) at 5 mM inhibited chitinase activity to 25% while Ca super(2+), Mg super(2+) and Ba super(2+) had no effect at the same concentration. The purified enzyme degraded mycelia of Aspergillus niger.

5.The novel method for isolating chitinolytic bacteria and its application in screening for hyperchitinase producing mutant of Alcaligenes xylosoxydans

To develop a novel, rapid and effective screening method for chitinase producing bacteria, a simple and rapid technique for screening of potential chitinolytic bacteria has been developed using the chitin binding dye calcofluor white M2R in chitin agar. Microorganisms possessing high chitinolytic potential gave a clear zone under ultraviolet light after 24-48 h of incubation. This method was successfully applied for isolating the hyperchitinase mutant of Alcaligenes xylosoxydans. The mutant Alc. xylosoxydans EMS 33 was found to produce 3.4 times more chitinase than the wild type. In this study, the screening method for chitinase producing bacteria has been developed and it was applied to screen chitinase-overproducing mutant of Alc. xylosoxydans. The novel screening method for chitinase producer is more sensitive, rapid, user-friendly and reliable, which can also be used for screening of recombinants having chitinase gene

參考資料:

1.Lindberg, LE; Willfoer, SM; Holmbom, BR.Antibacterial effects of knotwood extractives on paper mill bacteria

Journal of Industrial Microbiology & Biotechnology [J. Ind. Microbiol. Biotechnol.]. Vol. 31, no. 3, pp. 137-147. Mar 2004

2..Macmil, SL; Vaidya, RJ*; Vyas, PR; Chhatpar, HS  Production of Alcaligenes xylosoxydans EMS33 in a Bench-scale Fermenter

World Journal of Microbiology & Biotechnology [World J. Microbiol. Biotechnol.]. Vol. 21, no. 6-7, pp. 1215-1221. Oct 2005.

3..Vaidya, R; Roy, S; Macmil, S; Gandhi, S; Vyas, P; Chhatpar, HS.Purification and characterization of chitinase from Alcaligenes xylosoxydans.Biotechnology Letters [Biotechnol. Lett.]. Vol. 25, no. 9, pp. 715-717. 1 May 2003.

4..Vaidya, R; Macmil, S; Vyas, P; Chhatpar, H*.The novel method for isolating chitinolytic bacteria and its application in screening for hyperchitinase producing mutant of Alcaligenes xylosoxydans.Letters in Applied Microbiology [Lett. Appl. Microbiol.]. Vol. 36, no. 3, pp. 129-134. Mar 2003.

5..Yoshimune, K; Esaki, N; Moriguchi, M.Site-directed mutagenesis alters DnaK-dependent folding process.Biochemical and Biophysical Research Communications [Biochem. Biophys. Res. Commun.]. Vol. 326, no. 1, pp. 74-78. 31 Dec 2004.