Clostridium tyrobutyricum ATCC 25755 is an acidogenic bacterium capable of utilizing xylose for the fermentation production of butyrate. Hot water extraction of hardwood lingocellulose is an efficient method of producing xylose where autohydrolysis of xylan is catalysed by acetate originating from acetyl groups present in hemicellulose. The presence of acetic acid in the hydrolysate might have ...

In the yeast Zygosaccharomyces bailii ISA 1307, respiration and fermentation of glucose were exponentially inhibited by ethanol, both processes displaying similar sensitivity to the alcohol. Moreover, the degree of inhibition on fermentation was of the same magnitude as that reported for Saccharomyces cerevisiae. Acetic acid also inhibited these two metabolic processes in Z. bailii, with the ki...

A mathematical model is developed for converting between the two measurement bases commonly used in the construction of growth profiles in solid-state fermentation, namely absolute mass ratio m(dry biomass)/m(initial dry matter) and relative mass ratio m(dry biomass)/m(dry matter). These are not equivalent, due to the loss of dry matter as CO2 during the fermentation. The model is equally appli...

We studied the influence of cold temperature (10oC) on the fermentation of maltose by a S. cerevisiae wild-type strain, and a csf1∆ mutant impaired in glucose and leucine uptake at low temperatures. Cold temperature affected the fermentation kinetics by decreasing the growth rate and the final cell yield, with almost no ethanol been produced from maltose by the wild-type cells at 10oC. The csf1...

2 Faculty of Electrical Engineering, Department of Measurement and Robotics, Tržaška 25, 1000 Ljubljana, Slovenia __________________________________________________________________________________ Abstract 168 hour old Saccharomyces cerevisiae wine yeast cells on Petri dishes were exposed to a homogenous static magnetic field of 140 mT for periods of 24, 48 or 72 hours and then used as inoculum...

The recent start-up of several full-scale 'second generation' ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineerin...

The kinetics of alcoholic fermentation was evaluated using the following substrates: molasses, urea, and diamine phosphate (MUDP); molasses and guava seed flour (MGSF); and molasses and dry mycelium of Aspergillus niger (MMAN). The fermentations were done using Saccharomyces cerevisiae under anaerobic conditions, 32°C, and pH 4.6. For each fermentation substrate the effect of the nitrogen sourc...

Mathematical models of wine fermentation kinetics promise early diagnosis of stuck or sluggish winemaking processes as well as better matching of industrial yeast strains to specific vineyards. The economic impact of these challenges is significant: worldwide losses from stuck or sluggish fermentations are estimated at 7 billion AC annually, and yeast starter production is a highly competitive ...

In the last years the use of a multistarter fermentation process has been proposed to improve the organoleptic characteristics of wines. In the present study the fermentation performances and the interactions of mixed and sequential cultures of Hanseniasporauvarum, Candida zemplinina, and a strain of Saccharomycescerevisiae isolated from organic musts were investigated. To evaluate the oenologi...

Biomass and other carbonaceous materials can be gasified to produce syngas with high concentrations of CO and H2. Feedstock materials include wood, dedicated energy crops, grain wastes, manufacturing or municipal wastes, natural gas, petroleum and chemical wastes, lignin, coal and tires. Syngas fermentation converts CO and H2 to alcohols and organic acids and uses concepts applicable in ferment...