Fermentation robustness

Maturation regimes vary from as tittle change as possible in many white and pink wines (stainless steel tanks, cool storage, minimum time) to considerable modification in red table and a few white table wines. Fermentation and storage in fairly new 200-L barrels for about 6 mo is not uncommon for Chardoimay and white Burgundy wines. Many robust red table wines such as those from Cabernet Sauvignon grapes are often stored similarly, after fermentation and initial clarification, for up to about 3 yr in such barrels. 

Source A product of whiskey fermentation (quoted, Verschueren, 1983). Isobutyl acetate was identified as a volatile constituent released by fresh coffee beans Coffea canephora variety Robust at different stages of ripeness (Mathieu et al, 1998). 

Strain and cell line improvements with respect to productivity and robustness in fermentation... 

A bioprocess system has been monitored using a multi-analyzer system with the multivariate data used to model the process.27 The fed-batch E. coli bioprocess was monitored using an electronic nose, NIR, HPLC and quadrupole mass spectrometer in addition to the standard univariate probes such as a pH, temperature and dissolved oxygen electrode. The output of the various analyzers was used to develop a multivariate statistical process control (SPC) model for use on-line. The robustness and suitability of multivariate SPC were demonstrated with a tryptophan fermentation. 

Ethanol production depends not only on the sugar yield, but also on the fermentability of the solution. To investigate the fermentability of the pretreated com stover, fermentations were performed with baker s yeast. Baker s yeast has often been proposed as the best organism for the fermentation of lignocellulosic hydrolysates (28,29) and has the advantages that it is quite robust and was found to be less sensitive to inhibitors than cultivated yeast (30,31). 

Citric acid and vitamin C are examples of very large scale fermentation processes where the subsequent product isolation involves several bioseparations, including filtration, precipitation, evaporation, crystallization, and drying methods. The scale of operation requires careful choice of equipment which is robust, efficient in separating product from unwanted by-products, and cost effective to be competitive. 

Brent Pollock (Biomira Inc.) presented a talk on the rational development of a second-generation production process for recombinant human interleukin-2 that incorporates recent advances in cell expression systems, fermentation optimization, protein extraction, refolding, and purification. A key concept of this talk was to know thy protein. The driving forces for process changes were regulatory concerns/robustness, economics, the ability to use standard equipment, and the elimination of bottlenecks in the process. 

Therefore, the main challenge in developing robust microbes is to ensure efficient fermentations of the heterogeneous substrates released from biomass materials in the presence of inhibitors and fermentation products and under restricted pH and temperature conditions to ensure maximum product production. For the SSF process, special considerations are needed in searching for new microbes to allow optimum activities of hydrolytic enzymes. For the CBP process, pathways for producing endogenous hydrolytic enzymes should be included in new microbes. 

Conversion efficiency and robust fermentation of mixed-sugar lignocellulose-derived hydrolysates are critical for producing ethanol at low cost to realize a commercially viable biorefinery. Biomass sugars are typically released by thermochemical pretreatment followed by enzymatic hydrolysis of chopped or milled biomass. The pretreated soluble fraction of biomass is called the hydrolysate and the hydrolysate containing the insoluble... 

NPI-0052 is currently manufactured under cGMP through a robust saline fermentation process by S. tropica strain NPS21184. It was quite an effort to find the proper contract manufacturing organisations (CMOs) that would accept and adapt our saline fermentation process, developed in laboratory fermenters, to their industrial-scale production fermenters and also have the proper containment facility to handle the downstream processing (DSP) of the highly potent NPI-0052. 

A practical problem with non-Saccharomyces yeasts is that few strains are capable of completing fermentation, and in many cases only a small proportion of grape sugar will be fermented. Two strategies have evolved to enable complete fermentation these are cofermentation with a robust Saccharomyces strain and sequential fermentation, in which the non-Saccharomyces yeast and Saccharomyces strain are inoculated successively, in order to complete fermentation. Several studies have... 

Ceramic membranes are robust, easy to clean, and are available with large diameter feed channels, making them a strong technology for clarifying fermentation broths. 

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