Degenerative Processes in a Strain of Clostridium Butylicum

Kutzenok, A.; Aschner, M.

doi:10.1128/jb.64.6.829-836.1952

Cited by 62 publications

(29 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Degeneration typically is observed with repeated use of inocula derived from exponential phase cells [16,17,19,23]. These clostridia also degenerate in continuous culture [13,18,20,[24][25][26].…”

Section: Degeneration In Liquid Mediamentioning

confidence: 99%

“…As few studies reported in the literature used the same conditions of growth or inoculum transfer, it is not easy to dissect the effects of various environmental factors and culture conditions that lead to strain degeneration. It is clear that degenerate cells outgrow non-degenerate cells, but they do not grow more rapidly [17]. The growth advantage of degenerate cells may be due to continued cell division of uncommitted cells, while the non-degenerate cells stop dividing and start to differentiate.…”

Section: Degeneration In Liquid Mediamentioning

confidence: 99%

“…That is, they continue to multiply as vegetative cells and continue to form acids for some time. Strain degeneration is the general term applied to the loss of the ability to switch to the solventogenic and sporogenous pathways [16][17][18][19]. Laboratory-generated Sol-mutants are unable to form solvents and, by this definition, would also be degenerate.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Clostridial strain degeneration

Kashket

1995

FEMS Microbiology Reviews

View full text Add to dashboard Cite

Strain degeneration, the loss of the capacity to produce solvents and form spores, typically occurs when Clostridium acetobutylicum and related clostridia are repeatedly subcultured in batch culture or grown in continuous culture, as opposed to being grown from germinated, heat-treated spores. Several mechanisms for degeneration have been identified thus far. (i) Degeneration can be caused by excessive acidification of the culture during exponential growth. We present data interpreted to mean that C. beijerinckii (formerly C. acetobutylicum) NCIMB 8052 cells ferment glucose to acetic and butyric acids at an uncontrolled rate, so that, during rapid growth, the rate of acid production can exceed the rate of induction of the solventogenic pathway enzymes. As a result, the medium pH drops to bactericidal levels, and the cells cannot switch to solventogenesis and sporulation. The clostridia seem to be poised either to produce excess acids, or to initiate solventogenesis, depending on small differences in the rates of growth. (ii) We have isolated transposon-insertion mutants of C. beijerinckii NCIMB 8052 that are resistant to degeneration, suggesting the involvement of a regulatory region of the clostridial chromosome. (iii) Involvement of a global regulatory gene has been inferred in C. beijerinckii NCIMB 8052 which degenerates irreversibly in chemostat culture. (iv) Impairment of butanol formation due to a defect in NADH generation has been reported in an oligosporogenous strain which can revert to the non-degenerate phenotype. (v) In continuous culture, degenerate cells may be selected because they continue to divide, while the non-degenerate cells stop dividing and start differentiating.

show abstract

Section: Degeneration In Liquid Mediamentioning

confidence: 99%

Section: Degeneration In Liquid Mediamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Clostridial strain degeneration

Kashket

1995

FEMS Microbiology Reviews

View full text Add to dashboard Cite

show abstract

“…Past efforts to harvest clean spores from such a mixture have been unsuccessful (Collier 1957;Zoha and Sadoff 1958). Another challenge to spore production is due to a process known as strain degeneration (Kutzenok and Aschner 1952;Kashket and Cao 1995), where loss of spore production occurs after repeated subculturing or during growth in continuous culture (Kashket and Cao 1995). Degeneration appears to be facilitated by excessive acidification of cultures during exponential growth, and by a global regulatory gene responsible for strain degeneration (Kashket and Cao 1995).…”

Section: Introductionmentioning

confidence: 99%

Production and characterization of pureClostridiumspore suspensions

Yang

Crow-Willard

Ponce

2009

Journal of Applied Microbiology

View full text Add to dashboard Cite

Aims: A general protocol was derived for optimizing the production of pure, high concentration Clostridium endospore suspensions. Methods and Results: Two sporulation methods were developed that yielded high concentrations of notably pure Clostridium sporogenes, C. hungatei and C. GSA‐1 (Greenland ice core isolate) spore suspensions (10 ml of 109 spores ml−1 with >99% purity each). Each method was derived by evaluating combinations of three sporulation conditions, including freeze drying of inocula, heat shock treatment of cultures, and subsequent incubation at suboptimal temperatures that yielded the highest percentage of sporulation. Pure spore suspensions were characterized in terms of dipicolinic acid content, culturability, decimal reduction time (D) value for heat inactivation (100°C) and hydrophobicity. Conclusions: While some Clostridium species produce a high percentage of spores with heat shock treatment and suboptimal temperature incubation, other species require the additional step of freeze drying the inocula to achieve a high percentage of sporulation. Significance and Impact of the Study: Pure Clostridium spore suspensions are required for investigating species of medical and environmental importance. Defining the conditions for optimal spore production also provides insight into the underlying mechanisms of Clostridium sporulation.

show abstract

“…Clostridium butylicum [1,2] or Clostridium beijerinckii [3]. 2-Propanol may also be formed from acetone for disposal of reducing equivalents [4].…”

Section: Introductionmentioning

confidence: 99%

Secondary alcohols as hydrogen donors for CO2-reduction by methanogens

Zellner¹

1987

FEMS Microbiology Letters

View full text Add to dashboard Cite

SUMMARYOut of 22 methanogens Methanobacterium formicicum, Methanobacterium bryantii M.o.H., Methanogenium marisnigri, Methanomicrobium paynteri, Methanocorpusculum paroum and the new coccoid methanogenic isolates GKZPZ and SZSXXZ were found to grow at the expense of 2-propanol and 2-butanol + CO 2. 2-Propanol was oxidized to acetone and 2-butanol was converted to 2-butanone during CO2-reduction to methane.Growth was poor compared to that on Hz/CO 2, and in the presence of both, 2-propanol and H 2, molecular hydrogen was the preferred reductant. Acetone, formed during oxidation of 2-propanol in the absence of hydrogen, was reduced again to 2-propanol, when the culture was supplied with H2/CO 2. Ethanol, 1-propanol, 1-butanol, 2-pen-tanol and cyclohexanol could not serve as hydrogen donors for methanogenesis.

show abstract

Degenerative Processes in a Strain of Clostridium Butylicum

Cited by 62 publications

References 9 publications

Clostridial strain degeneration

Clostridial strain degeneration

Production and characterization of pureClostridiumspore suspensions

Secondary alcohols as hydrogen donors for CO2-reduction by methanogens

Contact Info

Product

Resources

About