Rhodotorula

L-Phenylalanine can be synthesised from trims-cinnamic add (Figure A8.12) catalysed by a L-phenylalanine ammonia-lyase from Rhodococcus glutinis. The commercialisation of the process was limited by the low conversion (70%), low stability of the biocatalyst and die severe inhibition exerted by trims-cinnamic add. These problems were largely overcome by researchers at Genex. The process, commercialised for a short period by Gen ex, involves a cell-free preparation of phenylalanine-ammonia-lyase activity from Rhodotorula rubra. 

The process uses cells of Rhodotorula minuta entrapped in polyurethane. These cells selectively hydrolyse the L-ester. The remaining D-menthyl succinate is then hydrolysed and the 15-menthol racemised via D-menthone and then recycled. We have represented this process in Figure 9.9. 

Figure 9.9 Resolution of DL-menthol using an esterase from Rhodotorula minuta var texensis.

The L-menthol could be recovered by hydrolysing the L-menthyl-5-phenylvalerate. You might anticipate using an esterase to carry out this hydrolysis such as the enzyme from Rhodotorula minuta described in the text. 

From culture of Sporidiobolus johnsonii (ATCC 20490), Sporidiobolus ruinenii (ATCC-20489), Oosporidium margaritiferum (ATCC 10676), Rhodotorula muciladinosa (AHM 3946), Xanthomonas stewartii (Pasteur-No. 1035 and 1036). 

Liu A, Neilands JB (1984) Mutational Analysis of Rhodotorulic Acid Synthesis in Rhodotorula philimanae. 58 97-106 Livage J, see Henry M (1991) 77 153-206... 

Ring fission clearly occurs during the metabolism of phenol (Walker 1973) by the yeast Rhodotorula glutinis, and of aromatic acids by various fungi (Cain et al. 1968 Durham et al. 1984 Gupta et al. 1986). 

Durham DR, CG McNamee, DP Stewart (1984) Dissimilation of aromatic compounds in Rhodotorula grami-nis biochemical characterization of pleiotrophically negative mutants. J Bacteriol 160 771-777. 

Gupta JK, C Jebsen, H Kneifel (1986) Sinapic acid degradation by the yeast Rhodotorula graminis. J Gen Microbiol 132 2793-2799. 

Middelhoven WJ, F Spaaij (1997) Rhodotorula cresolica sp. nov., a cresol-assrmilating yeast species isolated from soil. Int J Syst Bacterial 47 324-327. 

Walker N (1973) Metabolism of chlorophenols by Rhodotorula glutinis. Soil Biol Biochem 5 525-530. 

D-Aminoacid oxidase has been isolated from a nnmber of yeasts, and the nucleotide sequence of the enzyme from Rhodotorula gracilis ATCC 26217 has been established (Alonso et al. 1998). The gene could be overexpressed in Escherichia coli, and levels of the enzyme were greater under conditions of low aeration the enzyme isolated from the recombinant organisms was apparently the apoenzyme since maximum activity required the presence of FAD. 

Alonso J, JL Barredo, B Diez, E Mellado, E Salto, JL Garcia, E Cortes (1998) D-amino-acid oxidase gene from Rhodotorula gracilis (Rhodosporidium toruloides) ATCC 26217. Microbiology (UK) 144 1095-1101. 

Wondrack LM, C-A Hsu, MT Abbott (1978) Thymine-7-hydroxylase and pyrimidine deoxyribonucleoside 2 -hydroxylase activities m Rhodotorula glutinis. J Biol Chem 253 6511-6515. 

A cytochrome P450 has been purified from Saccharomyces cerevisiae that has benzo[a]pyrene hydroxylase activity (King et al. 1984), and metabolizes benzo[fl]pyrene to 3- and 9-hydroxybenzo[fl]pyrene and benzo[fl]pyrene-7,8-dihydrodiol (Wiseman and Woods 1979). The transformation of PAHs by Candida Upolytica produced predominantly monohydroxyl-ated products naphth-l-ol from naphthalene, 4-hydroxybiphenyl from biphenyl and 3- and 9-hydroxybenzo[fl]pyrene from benzo[fl]pyrene (Cerniglia and Crow 1981). The transformation of phenanthrene was demonstrated in a number of yeasts isolated from littoral sediments and of these, Trichosporumpenicillatum was the most active. In contrast, biotransformation of benz[fl]anthracene by Candida krusei and Rhodotorula minuta was much slower (MacGillivray and Shiaris 1993). 

Unusual 2-ketoglutarate-dependent dioxygenations have been found in the yeast Rhodotorula glutinis ... 

Wetzstein H-G, N Schmeer, W Karl (1997) Degradation of the fluoroquinolone enrofloxacin by the brown-rot fungus Gleophyllum striatum identification of metabolites. Appl Environ Microbiol 63 4272-4281. Wondrack LM, C-A Hsu, MT Abbott (1978) Thymine-7-hydroxylase and pyrimidine deoxyribonucleoside 2 -hydroxylase activities in Rhodotorula glutinis. J Biol Chem 253 6511-6515. 

Other workers including Jakubowski et. al. (1983) have found many different yeast and mould contaminants comprising most of the well known biodeteriogenic species such as Aspergillus, Fusarium, Geotrichum, Penicillium, Scopulariopsis, Saccharomyces and Torula. In addition, the author has also isolated Rhodotorula and Sporobolornyces on a number of occasions. 

Formation of insoluble sulphides from H2S production by sulphate reducing bacteria can bring about blackening of products (Figure 11) and some bacteria such as Serratia and Flavobacteria species and yeasts, including Rhodotorula can give pink or yellow discolorations. Other bacteria such as the Pseudomonads can produce fluorescent pigments. 

Rhodotorulic acid Hydroxamic acid 2 Species of Rhodotorula, Sporo-bolomyces, Sporidiobolus, Leuco-sporidium and Rhodosporidium... 

The yeasts also have been evaluated for antifungal activity. Spadaro and others (2008) reported that Hanseniaspora uvarum, Rhodotorula spp., and Metschnikowia pulcherrima reduced the development of P. expansum on apples. In this work the biocontrol effectiveness was assessed on four apple cultivars, Golden Delicious, Stark Delicious, Granny Smith, and Royal Gala. The efficacy was higher on the cv. Golden Delicious. 

One of the first reports on yeast-mediated color removal by a putative process of biosorption of azo dyes by yeast (Rhodotorula sp.) biomass belongs to [31]. Yeast species such as Kluveromyces marxianus removed the diazo dye remazol black B [10], Candida catenulata and Candida kefyr removed more than 90% of amaranth by biosorption [6]. Biosorption uptake of the textile azo dyes remazol blue, reactive black, and reactive red by S. cerevisiae and C. tropicalis varied according to the selected dye, dye concentration, and exposure time [5, 7]. In a recent screening work carried out by [32], from the 44 yeast strains tested for their decolorization ability, 12 of them removed the dye Reactive Brilliant Red K-2BP by biosorption, among them the following were identified S. cerevisiae, Saccharomyces uvarum, Torulopsis Candida, and Saccharomycopsis lipolytica. 

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