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C Rolz

Publications and source records attributed to C Rolz.

13 recordsLinked to original sources
PubMed1990

[Chemical and biochemical characteristics of the microbial biomass].

The nutritional potential of microbial biomass products is determined by their chemical and biochemical characteristics. The same vary according to the microbial species, the source of nutrients employed for their growth, the operational mode of bioreactor and, finally, due to processing effects during growth or in the unit operations employed for its recovery. In this review, a detailed chemical description is given for those microbial biomass products from algae, bacteria, yeast and fungi, which have been either commercially produced or produced for demonstration purposes in pilot installations. Lastly, the effect of some operational parameters over the biomass chemical composition are illustrated in order to show general tendencies that have been experimentally observed, without a claim to be an exhaustive literature review of all aspects involved.

Bacterial Proteins↗
PubMed1989

A protein concentrate from distillery yeast, and its application to supplement corn tortillas.

The purpose of this study was to increase the protein quality of tortillas supplementing them with a protein concentrate obtained from the yeast (Saccharomyces cerevisiae) cream from an alcohol distillery. Rupture of the yeast cell wall was studied, and a procedure for obtaining a high percentage of broken cells from the yeast was developed. A protein concentrate was obtained from the cell-wall free portion. Techniques were developed to obtain the protein concentrate with a low level of nucleic acids. The latter were reduced 91%, and the protein increased 55% with respect to the initial yeast. Different levels of protein concentrate were added to dough made from corn of the Nutricta variety. The resulting tortillas were submitted to a taste panel for sensory evaluation, and the results were statistically analyzed. The highest level of supplementation that did not affect negatively acceptation by the panel was 18% dry weight. In the tortillas with the highest acceptable level of supplementation, protein content increased 60% when compared to the control tortillas, and a significant improvement in lysine content was observed. Nucleic acid content was low, having been reduced to levels which did not represent a limiting factor for the use of yeast in a product destined for human consumption.

Amino Acids, Essential↗
PubMed1986

Biodelignification of lemon grass and citronella bagasse by white-rot fungi.

Twelve white-rot fungi were grown in solid-state culture on lemon grass (Cymbopogon citratus) and citronella (Cymbopogon winterianus) bagasse. The two lignocellulosic substrates had 11% permanganate lignin and a holocellulose fraction of 58%. After 5 to 6 weeks at 20 degrees C, nine fungi produced a solid residue from lemon grass with a higher in vitro dry matter enzyme digestibility than the original bagasse; seven did the same for citronella. The best fungus for both substrates was Bondarzewia berkeleyi; it increased the in vitro dry matter enzyme digestibility to 22 and 24% for lemon grass and citronella, respectively. The increases were correlated with weight loss and lignin loss. All fungi decreased lignin contents: 36% of the original value for lemon grass and 28% for citronella. Practically all fungi showed a preference for hemicellulose over cellulose.

Journal Article↗
PubMed1980

Ethanol from Sugar Cane: Flask Experiments Using the EX-FERM Technique.

Alcohol production at the laboratory scale from sugar cane pieces by the EX-FERM technique was studied with 37 strains of Saccharomyces spp. The EX-FERM process is novel in that it employs the simultaneous extraction and fermentation of the sucrose in a cane-water suspension. Two types of cane treatments were used: chips and shredded pith, either fresh or dried. A mother culture of the yeast was prepared in enriched cane juice and then added to the cane-water mixture. After static fermentation for 40 h at 30 degrees C, the cane was removed, and fresh cane was added to the yeast-alcohol broth. After an additional 24 h, the cane was again removed and the liquor was analyzed. After the first 40-h cycle, sugar consumption was above 99% with 10 of the 37 yeast strains tested, and ethanol reached levels of 1.29 to 4.00 g per 100 ml, depending on the yeast strain. The final ethanol concentration reached 4.27 to 5.37 g per 100 ml, and sugar consumption was above 98% in three cases during a second EX-FERM cycle employing previously air-dried chips and pith. Product yields were within accepted values. Cane treatment did not appear to affect the results at this level.

Journal Article↗