Alcaligenes faecalis, depolymerase

The poly(HA) depolymerases of the bacteria Alcaligenes faecalis (strains AE122 and Tl), Comamonas acidovorans, Comamonas testosteroni, Comamonas sp., Pseudomonas fluorescens, Pseudomonas lemoignei, Pseudomonas stutzeri, Ralstonia pickettii, Streptomyces exfoliatus, and of the fungi Paecilomyces lilaci-nus, Penicillium funiculosum, and Penicillium pinophilum have been purified and characterized (for details see Table 1). Poly(HA) depolymerases share several characteristics ... 

Iwata T, Doi Y, Tanaka T, Akehata T, Shiromo M, Teramachi S (1997b) Enzymatic degradation and adsorption on poly[(/J)-3-hydroxybutyrate] single crystals with two types of extracellular PHB depolymerases from Comamonas acidovorans YM1609 and Alcaligenes faecalis Tl. Macromolecules 30 5290-5296... 

Tanio T, Fukui T, Shirakura Y, Saito T, Tomita K, Kaiho T, Masamune S (1982) An extracellular poly(3-hydroxybutyrate) depolymerase from Alcaligenes faecalis. Eur J Biochem 124 71-77 Tesema Y, Raghavan D, Stubbs J (2(X)5) Bone cell viabUity on methacrylic add grafted and collagen immobilized porous poly(3-hydroxybutyrate-co-3-hydroxyvalerate). J Appl Polym Sd 98(5) 1916-1921... 

The mechanism of extracellular degradation of PHA is not yet well understood. A wide variety of microorganisms (fungi, aerobic and anaerobic bacteria) have been implicated but only Pseudomonas lemoignei, Alcaligenes faecalis, and Comamonas sp. have been studied in detail. Production of extracellular PHA depolymerases is induced by the presence of PHA as the sole carbon source. Generally, a PHB depolymerase acts from the hydroxyl terminus to form dimers (or trimers, depending on the depolymerase) and a trace amoimt of monomer. An... 

Bachmann BM, Seebach D. Investigation of the enzymatic cleavage of diastereomeric oligo(3-hydroxybutanoates) containing two to eight HB units. A model for the stereoselectivity of PHB depolymerase from Alcaligenes faecalis T-1. Macromolecules 1999 32 1777-1784. 

Shirakura, Y, Fukui, T., Saito, T., Okamoto, Y, Narikawa, T, Koide, K., Tomita, K., Takemasa, T. and Masamune, S. (1986), Degradation of poly(3-hydroxybutyrate) by poly(3-hydroxybutyrate) depolymerase from Alcaligenes faecalis Tj , Biochim. Biophys. Acta. 880 (1), 46-53. 

Tanio T, Fukui T, Saito T, Tomita K, Kaiho T, Masamune S (1982) An extracellular poly(P-hydroxybutyrate) depolymerase from Alcaligenes faecalis. Eur J Biochem 124 71-77... 

Similar properties are also shown by the incorporation of 3-hydroxypropionate (3HP) into the P[3HB] sequence [64]. Like 4HB, 3HP do not possess chirality. Since the discovery of 3HP as a member of the PHA family [65], much work has been done to produce P[3HB-co-3HP] containing various amounts (0-88 mol%) of 3HP units [66,67]. The investigation of solid-state structure [68] and biodegradability [67] of these copolymers with various 3HP units showed much similarity to the copolymers of P[3HB-co-4HB] [69, 70]. However, in contrast to P[4HB] homopolymer, the homopolymer of P[3HP] was hardly eroded in river water [69] but could be degraded by the P[3HB] depolymerase (EC 3.1.1.75) (see Section 7.5) purified from Alcaligenes faecalis [71]. 

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