Document Detail

Ingredient selection for plastic composite supports for L-(+)-lactic acid biofilm fermentation by Lactobacillus casei subsp. rhamnosus.
MedLine Citation:
PMID:  9212402     Owner:  NLM     Status:  MEDLINE    
Plastic composite supports containing 50% agricultural products (oat hulls, soybean hulls, yeast extract, soybean flour, dried bovine erythrocytes, bovine albumin, and/or mineral salts) and 50% (wt/wt) polypropylene were produced by high-temperature twin-screw extrusion. The research employed two half sets of a five-factorial fractional design (2(5 - 1)) to evaluate the effects of different agricultural components on the properties of the plastic composite supports and to select the best plastic composite support formulation for lactic acid fermentation. The biofilm population was affected by the contact angle and relative hydrophobicity of the supports (r = 0.79 to 0.82). Lactic acid was produced by the suspended cells (r = 0.96) and the biofilm on the plastic composite support discs (r = 0.85). Incorporation of yeast extract into plastic composite supports enhanced growth of free and attached cells in minimal medium (P < 0.0001). The presence of soybean hulls, yeast extract, or mineral salts in plastic composite supports produced less hydrophobic supports (P < 0.0001) and enhanced cell attachment (P < 0.03). Under all conditions, suspended-cell and polypropylene disc controls gave negligible lactic acid production and cell density. Plastic composite supports containing soybean hulls, yeast extract, soybean flour, bovine albumin, and mineral salts gave the highest biofilm population (2.3 x 10(9) CFU/g of support), cell density (absorbance of 1.8 at 620 nm), and lactic acid concentration (7.6 g/liter) in minimal medium.
K L Ho; A L Pometto; P N Hinz; J S Dickson; A Demirci
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  63     ISSN:  0099-2240     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  1997 Jul 
Date Detail:
Created Date:  1997-08-12     Completed Date:  1997-08-12     Revised Date:  2010-09-10    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2516-23     Citation Subset:  IM    
Department of Food Science and Human Nutrition, Iowa State University, Ames 50011, USA.
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MeSH Terms
Avena sativa / metabolism
Biofilms / growth & development*
Colony Count, Microbial
Culture Media / analysis*,  metabolism
Erythrocytes / metabolism
Lactic Acid / metabolism*
Lactobacillus casei / metabolism*,  physiology*,  ultrastructure
Microscopy, Electron, Scanning
Plastics / metabolism
Salts / metabolism
Serum Albumin, Bovine
Soybeans / metabolism
Water / metabolism
Yeasts / metabolism
Reg. No./Substance:
0/Culture Media; 0/Plastics; 0/Salts; 0/Serum Albumin, Bovine; 50-21-5/Lactic Acid; 7732-18-5/Water

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