Chlorine dioxide against bacteria and yeasts from the alcoholic fermentation

Abstract

The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant bacteria (Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides) from alcoholic fermentation, through the method of minimum inhibitory concentration (MIC), as well as its effect on the industrial yeast inoculum. Lower MIC was found for B. subtilis (10 ppm) and Leuconostoc mesenteroides (50 ppm) than for Lactobacillus fermentum (75 ppm) and Lactobacillus plantarum (125 ppm). Additionally, these concentrations of chlorine dioxide had similar effects on bacteria as 3 ppm of Kamoran® (recommended dosage for fermentation tanks), exception for B. subtilis, which could not be controlled at this Kamoran® dosage. The growth of industrial yeasts was affected when the concentration of chlorine dioxide was higher than 50 ppm, but the effect was slightly dependent on the type of yeast strain. Smooth yeast colonies (dispersed cells) seemed to be more sensitive than wrinkled yeast colonies (clustered cells/pseudohyphal growth), both isolated from an alcoholproducing unit during the 2006/2007 sugar cane harvest. The main advantage in the usage of chlorine dioxide that it can replace antibiotics, avoiding the selection of resistant populations of microorganisms.

Investigation of the stabilization and preservation of sweet sorghum juices

“…However, a biocide that evaporates after its use would be useful. Choride dioxide (ClO 2 ) has been used as a bacterial decontaminant of water and equipment, and against numerous lactic acid bacteria in alcoholic fermentations (Meneghin et al, 2008) and is known to evaporate after usage. Ultraviolet (UV) light radiation has been used for many years in pharmaceutical, electronic, aquaculture, and maple sugar industries, and more recently in food and beverage industries, to inactivate many types of microorganisms (Sipple et al, 1970;Morselli and Whalen, 1983; Guerrero-Beltran and BarbosaCanovas, 2004;Knights, 2013).…”

Anti-Contamination Strategies for Yeast Fermentations

“…Hydrogen peroxide at concentrations of 1 to 10 mmol/L and sulfite at concentrations of 100 to 400 mg/L effectively reduced selected LAB strains such as L. casei and L. fermentum during cell-recycled ethanol fermentations [75]. One of the well-known biocides used in water treatment, chlorine dioxide (ClO 2 ), has been tested to control bacterial contamination by LAB contaminants (L. plantarum, L. fermentum, and L. mesenteroides) and Bacillus subtilis in alcohol fermentation [76]. Chlorine dioxide in the range of 10-200 ppm successfully inhibited the growth of the bacterial contaminants, but a concentration higher than 50 ppm also affected the growth of industrial yeasts [76].…”

“…One of the well-known biocides used in water treatment, chlorine dioxide (ClO 2 ), has been tested to control bacterial contamination by LAB contaminants (L. plantarum, L. fermentum, and L. mesenteroides) and Bacillus subtilis in alcohol fermentation [76]. Chlorine dioxide in the range of 10-200 ppm successfully inhibited the growth of the bacterial contaminants, but a concentration higher than 50 ppm also affected the growth of industrial yeasts [76]. One study reported that the use of chemical 3,4,4,'-trichlorocarbanilide (TCC) at a concentration of 0.075 g/L resulted in excellent control of bacterial growth (L. fermentum) for multiple fermentation cycles in fed-batch ethanol fermentation when used with sodium dodecyl sulfate [77].…”

The Two Faces ofLeuconostoc mesenteroidesin Food Systems

“…(140) Nonetheless, Leuconostoc genus is sensitive to ethanol and presents a shortlife inside the tanks. (141) In wine fermentation, the glycerol oxidation carried out by Lc. mesenteroides and lactobacilli strains generates acrolein.…”