Novel stabilization of phenylalanine ammonia-lyase catalyst during bioconversion of trans-cinnamic acid to l-phenylalanine

Enhancement of l-Phenylalanine production by β-cyclodextrin

“…1, the concentration of L-Phe increases dramatically from 34 mmol/l, showing a maximum at 135 mmol/l, then sharply decreases to 408 mmol/l, which indicates that PAL activity is strongly influenced by t-Ca concentration. The lowest inhibitory concentration of t-Ca is 135 mmol/l, similar to the results reported by Yamada et al (1981) and Evans et al (1987).…”

“…In the enzymatic reaction, the PAL activity was inhibited by t-Ca with high concentration, reported in literatures (Evans et al, 1987;Yamada et al, 1981). At reaction conditions of 1 mol/l NH 3 AE H 2 O, pH 9.8, 150 rpm and 30°C, the effects of t-Ca on PAL activity were studied with the concentration of t-Ca ranging from 34 mmol/l to 408 mmol/l.…”

Expression in E. coli of the gene encoding phenylalanine ammonia-lyase from Rhodosporidium toruloides

“…The enzyme has received considerable interest as a possible candidate in oral enzyme therapy of patients suffering from phenylketonuria (Inoue et al 1986;Hoskins et al 1980) and in quantitative analysis of serum phenylalanine (Koyama 1984). Furthermore, the reverse reaction has been exploited commercially in the production of L-phenylalanine, which is a precursor for the high powered artificial sweetener Aspartame (Hamilton et al 1985;Evans et al 1987a). …”

Use of Enzymes in the Synthesis of Amino Acids

“…The PAL-mediated bioconversion to L-phenylalanine has been improved over the last decades using both anaerobic (by N 2 -sparging) and static conditions [149,150], or by applying reducing conditions, for example, by the addition of 2-mercaptoethanol or thioglycolic acid [151,152], as well as by addition of other types of compounds [142,150,151] and the omission of chlorine ions [150,153]. All these stabilizing factors could successfully be combined, enabling the reuse of the yeast cells in six to eight consecutive L-phenylalanine synthesis runs [150,151].…”

“…All these stabilizing factors could successfully be combined, enabling the reuse of the yeast cells in six to eight consecutive L-phenylalanine synthesis runs [150,151]. In a different approach to improve the PAL-catalyzed L-phenylalanine synthesis, mutants of Rhodotorula graminis with increased cellular activity and an improved stability during fermentation and bioconversion have been obtained by classical strain improvement [154,155].…”