CARBON SOURCES AND THEIR EFFECT ON GROWTH, ACETIC ACID AND ETHANOL PRODUCTION BY BRETTANOMYCES BRUXELLENSIS IN BATCH CULTURE

The influence of available low‐cost carbohydrates as carbon sources on Brettanomyces bruxellensis growth, acetic acid and ethanol production was studied in order to ascertain the viability of this yeast to eventually become an industrial acetic acid producer. Six different raw materials were included as carbon sources (glucose, sugarcane molasses, refined cane sugar, pineapple, sugarcane and beet juices). B. bruxellensis develops in a complex culture medium like plant juices and sugarcane molasses better than in a medium with a simple carbohydrate such as glucose. The maximum acid acetic yield (0.24 g/g) and productivity (0.14 g/L/h) were attained in tests carried out with sugarcane molasses containing 60 g/L sucrose. The strain produced low levels of ethanol in a refined sugarcane medium, but was able to produce a substantial quantity of acetic acid (13 g/L).     

Reactions and Bonding of Sodium Disilicate Glass with Chromium

Reactions and reaction mechanisms occurring at sessile drop interfacial regions of sodium disilicate glass on chromium were identified at 1000°C and an ambient atmosphere of 2.7 × 10⁻⁴Pa with a p(O₂) of 1 × 10⁻¹⁵ and 1 × 10⁻⁵ Pa. Depending on the experimental conditions, the principal reactions were redox reactions of Cr⁰ with Na⁺ to form Cr²+ and Na⁰, Cr²+ with Na⁺ to form Cr³+ and Na⁺, Cr⁰ with Si⁴+ to form CrSi_x, alloy dendrites and Cr²⁺, and Cr²⁺ with Si⁴⁺ to form Cr³⁺ and SiO(gas). Adherence was developed when the interfacial region was saturated with Cr³⁺, i.e., Cr₂O₃.     

Kinetics of Iron-Sodium Disilicate Reactions and Wetting

Thermogravimetric and sessile drop measurements were used to study kinetics of redox reactions between sodium disilicate glass and iron. Two redox reaction sequences were identified; both introduced ferrous oxide into the glass at the interface. One consists of formation of ferrous oxide at the interface by reduction of sodium ions in the glass; this is primarily dependent on the a (FeO) in the metal being less than one. The second consists of oxidation of ferrous ions in the glass by the reduction of sodium ions to form ferric ions which subsequently react with the iron to form ferrous oxide. The reaction rates were shown to be sensitive to temperature, time, total ambient pressure, partial pressure of sodium and oxygen in the atmosphere, and the a (FeO) in the iron. Decrease of contact angles and spreading occur with the redox reaction in which the metal plays an active role, i.e. whose a (FeO) is less than one and whose composition undergoes a change.     

COLOR PARAMETER CHANGES IN BANANA SLICES DURING OSMOTIC DEHYDRATION

ABSTRACT

Twenty-seven conditions of osmotic dehydration ( temperature 50, 60 and 70 ° C, pH 6, 7 and 8 and sucrose solution 50, 60 and 70 ° Brix) were applied to banana slices and results of L, hue, chroma and total difference of color were analyzed. Statistical analysis of L, chroma and hue changes in banana slices permitted to select five following treatments: 3 ( 50 ° Brix, temp. 70 ° C and pH 6.0), 10 (60 ° Brix, temp. 50 ° C and pH 6.0), 15 ( 60 ° Brix, temp. 70 ° C and pH 7.0 ), 17 ( 60 ° Brix, temp. 60 ° C and pH 8.0 ) and 25 ( 70 ° Brix, temp. 50 ° C and pH 8.0 ) as the most adequate conditions due to color changes that were not different in comparison to color parameters of raw ripe fruit chips.     

The DNA Sequence of Cosmid 14–13b from Chromosome XIV of Saccharomyces cerevisiae Reveals an Unusually High Number of Overlapping Open Reading Frames

This work is part of the effort for sequencing chromosome XIV of Saccharomyces cerevisiae. Cosmid 14–13b contains a 37·8 kb insert derived from a partial Sau3A digestion of the genome, cloned into the BamHI site of the vector Pou6. The strategy used for sequencing is based on the fragmentation of the whole cosmid by sonication, followed by shotgun sequencing on an Applied Biosystem DNA sequencer. The clones with inserts corresponding to the vector were identified by dot-blot hybridization, without the need of sequencing. The analysis of the DNA sequence reveals 29 open reading frames (ORFs) longer than 300 bases. Nine ORFs are internal to some other ORFs. Similarity searches against DNA and protein data banks show that six ORFs correspond to already known yeast genes (OMP1, PSU1, MLS1, RPC19, DBP2, CYB5) and one ORF matches the sequence of a putative yeast gene (ESBP6). The cosmid sequence has been submitted to the EMBL data bank under Accession Number Z69382.©1997 John Wiley & Sons, Ltd.     

SURVEY OF FOOD INGREDIENT-DDT REACTIONS UNDER THERMAL PROCESSING CONDITIONS

Aqueous solutions or suspensions of single or multiple food ingredients were heated at 100°C for 2 hr with carbon–14 labeled DDT. Thin-layer chromatography on alumina plates resolved the resulting mixtures into regions corresponding to R_f values for five known transformation products or analogs of DDT. The radioactivity of each plate region was related to the quantity of each product formed. DDT is relatively stable in heated water or buffer solutions of pH 3 to 8 as shown by recoveries of DDT (98–100%); at pH 8.1, approximately 4% of DDE was formed. The compositional changes in radioactive DDT due to heating with water-soluble vitamins, disphosphopyridine nucleotide, yeast nucleic acid, amino acids, peptides and casein were determined. The maximum reduction in DDT content of a suspension heated with a single component (cysteine hydrochloride) was 10%. A mixture of DDT with nine components heated for 2 hr produced a 20% reduction in DDT content.     

Study by Extended X-ray Absorption Fine-Structure Technique and Microscopy of the Chemical State of Yttrium in α-Polycrystalline Alumina

Yttrium-doped a-poly crystalline alumina was studied by microscopy observations and by extended X-ray absorption fine-structure experiments. The latter results were compared to those obtained for a standard Y₂O₃ powder and to theoretical spectra for Y₂O₃, and Y₃Al₅O₁₂ calculated on the basis of crystallographic data. Most of the yttrium in the doped alumina is precipitated as a Y₃Al₅O₁₂ phase. An observed threshold displacement involves a slight valence electron delocalization for the Y³⁺ ion.