Single-Cell Protein

Vasey, R.B.; Powell, Kimerly

doi:10.1080/02648725.1984.10647802

Cited by 32 publications

(24 citation statements)

References 10 publications

(4 reference statements)

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“…The impetus for much of the work in this area came from the commercial desire to produce a cheap and competitive source of single-cell protein, taking advantage of the ubiquitous nature and relative cheapness of methane, methanol and carbon monoxide. These applications have been extensively reviewed (Hamer and Harrison, 1980;Meyer, 1980Meyer, , 1981Smith, 1981;Vasey and Powell, 1984). The main characteristics desired in organisms for single-cell protein production are: These requirements have influenced the methods of isolation of methylotrophs and particularly the criteria for selecting organisms from isolation media.…”

Section: Isolation Of Methylotrophs and Ci-utilizing Autotrophsmentioning

confidence: 99%

“…G -C contents vary between 52% and 56%. They include organisms named as various Pseudomonas species, Methylomonas methylovora', 'Methylophilus methylotrophus' (the organism used by ICI for single-cell protein 'Pruteen' production; Vasey and Powell, 1984), Methylornonas aminofaciens', 'Methylomonas clara' and 'Methylomonas methanolica'. Anthony (1982) suggests that they could all be included in a single genus, 'Methylophilus'.…”

Section: Methanol and Methylated Aminesmentioning

confidence: 99%

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New Strategies for the Selective Isolation of Industrially Important Bacteria

Goodfellow

Williams

1986

Biotechnology and Genetic Engineering Reviews

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Section: Isolation Of Methylotrophs and Ci-utilizing Autotrophsmentioning

confidence: 99%

Section: Methanol and Methylated Aminesmentioning

confidence: 99%

New Strategies for the Selective Isolation of Industrially Important Bacteria

Goodfellow

Williams

1986

Biotechnology and Genetic Engineering Reviews

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“…These properties are attractive for the production of many useful materials, including amino acids, from methanol in fermentation. Although M. methylotrophus has been extensively studied with regard to fermentative production of SCP 2,3,15) and also in relation to oxidation of methanol at the initial stages of carbon and energy metabolism, 3,18,19) there has been little metabolic analysis of its amino acids biosynthesis.…”

mentioning

confidence: 99%

“…13,14) Among methylotrophic bacteria, M. methylotrophus possesses several advantages for industrial applications. 3,[15][16][17] These are: (1) high growth yield and growth rate, (2) applicability of recombinant DNA technology, (3) absence of spore formation and easy handling in culture and storage, and (4) moderately high optimal growth temperature. These properties are attractive for the production of many useful materials, including amino acids, from methanol in fermentation.…”

mentioning

confidence: 99%

Characterization of theL-Lysine Biosynthetic Pathway in the Obligate MethylotrophMethylophilus methylotrophus

Gunji

Tsujimoto

Shimaoka

et al. 2004

Bioscience, Biotechnology, and Biochemistry

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The L-lysine biosynthetic pathway of the gramnegative obligate methylotroph Methylophilus methylotrophus AS1 was examined through characterization of the enzymes aspartokinase (AK), aspartsemialdehyde dehydrogenase, dihydrodipicolinate synthase (DDPS), dihydrodipicolinate reductase, and diaminopimelate decarboxylase. The AK was inhibited by L-threonine and by a combination of L-threonine and L-lysine, but not by L-lysine alone, and the activity of DDPS was moderately reduced by L-lysine. In an L-lysine producing mutant (G49), isolated as an S-(2-aminoethyl)-Lcysteine (lysine analog) resistant strain, both AK and DDPS were partially resistant to feedback inhibition. The ask and dapA genes encoding AK and DDPS respectively were isolated from the parental strain, AS1, and its G49 derivative. Comparison of the sequences revealed a point mutation in each of these genes in G49. The mutation in the ask gene altered aspartic acid in a key region involved in the allosteric regulation common to AKs, while a novel mutation in the dapA gene altered tyrosine-106, which was assumed to be involved in the binding of L-lysine to DDPS.

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“…10515). This organism was extensively studied in the 1970s and has been industrialized on a large scale for the manufacturing of single-cell proteins (SCP) from methanol (56,63). During that period, a significant amount of research was conducted on the direct production of amino acids by fermentation from methanol (3,58).…”

mentioning

confidence: 99%

Aromatic Amino Acid Auxotrophs Constructed by Recombinant Marker Exchange in Methylophilus methylotrophus AS1 Cells Expressing the aroP -Encoded Transporter of Escherichia coli

Yomantas

Tokmakova

Gorshkova

et al. 2010

Appl Environ Microbiol

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The isolation of auxotrophic mutants, which is a prerequisite for a substantial genetic analysis and metabolic engineering of obligate methylotrophs, remains a rather complicated task. We describe a novel method of constructing mutants of the bacterium Methylophilus methylotrophus AS1 that are auxotrophic for aromatic amino acids. The procedure begins with the Mu-driven integration of the Escherichia coli gene aroP, which encodes the common aromatic amino acid transporter, into the genome of M. methylotrophus. The resulting recombinant strain, with improved permeability to certain amino acids and their analogues, was used for mutagenesis. Mutagenesis was carried out by recombinant substitution of the target genes in the chromosome by linear DNA using the FLP-excisable marker flanked with cloned homologous arms longer than 1,000 bp. M. methylotrophus AS1 genes trpE, tyrA, pheA, and aroG were cloned in E. coli, sequenced, disrupted in vitro using a Km r marker, and electroporated into an aroP carrier recipient strain. This approach led to the construction of a set of marker-less M. methylotrophus AS1 mutants auxotrophic for aromatic amino acids. Thus, introduction of foreign amino acid transporter genes appeared promising for the following isolation of desired auxotrophs on the basis of different methylotrophic bacteria.The nonpathogenic Gram-negative bacterium Methylophilus methylotrophus is able to grow efficiently using C 1 substrates (methanol, methylamine, or trimethylamine) as the sole source of carbon and energy, and it uses the ribulose monophosphate pathway for fixation of formaldehyde produced by the oxidation of methanol (36). Methanol has received considerable attention by the fermentation industry as an alternative substrate to the more generally used sugars from agricultural crops. It can be synthesized either from petrochemicals or renewable resources, such as biogas (48), and therefore the production of methanol does not compete directly with human food supplies. Methylotrophs can therefore be considered potentially useful strains for industrial biotechnology. M. methylotrophus AS1 is an obligate methylotroph originally isolated from activated sludge, and it has been deposited in the National Collections of Industrial, Marine and Food Bacteria (NCIMB; no. 10515). This organism was extensively studied in the 1970s and has been industrialized on a large scale for the manufacturing of single-cell proteins (SCP) from methanol (56, 63). During that period, a significant amount of research was conducted on the direct production of amino acids by fermentation from methanol (3, 58). Although initially promising, these efforts ultimately proved relatively unsatisfactory and impractical, due primarily to the rather poor set of genetic tools that had been developed for methylotrophs.Over the last 5 years, several genomes of methylotrophs have been sequenced (8,20,29,37,65,67), and significant progress in elucidating their metabolism has been achieved (14). The number of tools available for the genetic and met...

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Single-Cell Protein

Cited by 32 publications

References 10 publications

New Strategies for the Selective Isolation of Industrially Important Bacteria

New Strategies for the Selective Isolation of Industrially Important Bacteria

Characterization of theL-Lysine Biosynthetic Pathway in the Obligate MethylotrophMethylophilus methylotrophus

Aromatic Amino Acid Auxotrophs Constructed by Recombinant Marker Exchange in Methylophilus methylotrophus AS1 Cells Expressing the aroP -Encoded Transporter of Escherichia coli

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