A structured model for microbial growth and product formation

1978 ◽  
Vol 5 (3) ◽  
pp. 177-188 ◽  
Author(s):  
R. Larsen ◽  
L. Kjaergaard
Keyword(s):  
Microbial Growth ◽  
Product Formation ◽  
Structured Model

scholarly journals Physiological and Transcriptional Responses of Different Industrial Microbes at Near-Zero Specific Growth Rates

2015 ◽  
Vol 81 (17) ◽  
pp. 5662-5670 ◽  
Author(s):  
Onur Ercan ◽  
Markus M. M. Bisschops ◽  
Wout Overkamp ◽  
Thomas R. Jørgensen ◽  
Arthur F. Ram ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Rates ◽  
Microbial Growth ◽  
Current Knowledge ◽  
Product Formation ◽  
Natural Ecosystems ◽  
Transcriptional Responses ◽  
Content Type ◽  
Growth Physiology ◽  
Zero Growth

ABSTRACTThe current knowledge of the physiology and gene expression of industrially relevant microorganisms is largely based on laboratory studies under conditions of rapid growth and high metabolic activity. However, in natural ecosystems and industrial processes, microbes frequently encounter severe calorie restriction. As a consequence, microbial growth rates in such settings can be extremely slow and even approach zero. Furthermore, uncoupling microbial growth from product formation, while cellular integrity and activity are maintained, offers perspectives that are economically highly interesting. Retentostat cultures have been employed to investigate microbial physiology at (near-)zero growth rates. This minireview compares information from recent physiological and gene expression studies on retentostat cultures of the industrially relevant microorganismsLactobacillus plantarum,Lactococcus lactis,Bacillus subtilis,Saccharomyces cerevisiae, andAspergillus niger. Shared responses of these organisms to (near-)zero growth rates include increased stress tolerance and a downregulation of genes involved in protein synthesis. Other adaptations, such as changes in morphology and (secondary) metabolite production, were species specific. This comparison underlines the industrial and scientific significance of further research on microbial (near-)zero growth physiology.

scholarly journals Oil Palm Frond Juice as Future Fermentation Substrate: A Feasibility Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Che Mohd Hakiman Che Maail ◽  
Hidayah Ariffin ◽  
Mohd Ali Hassan ◽  
Umi Kalsom Md Shah ◽  
Yoshihito Shirai
Keyword(s):  
Oil Palm ◽  
Microbial Growth ◽  
Storage Stability ◽  
Product Formation ◽  
Storage Duration ◽  
Industrial Fermentation ◽  
Oil Palm Frond ◽  
And Storage ◽  
Palm Frond ◽  
Fermentation Substrate

Oil palm frond (OPF) juice is a potential industrial fermentation substrate as it has high sugars content and the OPF are readily available daily. However, maximum sugars yield and storage stability of the OPF juice are yet to be determined. This study was conducted to determine the effect of physical pretreatment and storage duration of OPF petiole on sugars yield. Storage stability of OPF juice at different storing conditions was also investigated. It was found that OPF petiole squeezed by hydraulic pressing machine gave the highest sugars recovery at almost 40 g/kg, accounting for a recovery yield of 88%. Storage of OPF petiole up to 72 hrs prior to squeezing reduced the free sugars by 11 g/kg. Concentrated OPF juice with 95% water removal had the best storage stability at both 4 and30°C, when it was stored for 10 days. Moreover, concentrated OPF syrup prepared by thermal processing did not give any Maillard effect on microbial growth. Based on our results, OPF juice meets all the criteria as a good fermentation substrate as it is renewable, consistently available, and easy to be obtained, it does not inhibit microbial growth and product formation, and it contains no impurities.

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