摘要:

AbstractMicrobial polysaccharides are rapidly emerging as a new and important source of polymeric materials. These biopolymers have novel and unique properties and already have found a wide range of applications in the food, pharmaceutical, and other industries. In view of the impending importance of polysaccharides as an industrial commodity, there is renewed interest in the area of product and process development. This paper summarizes the state‐of‐the art in polysaccharide fermentations. An attempt is being made to review the following areas: rheological characteristics of polysaccharide solutions, mixing and power requirements of polysaccharides and other highly viscous non‐Newtonian systems, oxygen mass transfer, and scale‐up problems encountered in polysaccharide fermen

ISSN:0006-3592    

DOI:10.1002/bit.260200702

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractXanthan gum is a heteropolysaccharide synthesized byXanthomonas campestrisNRRL B‐1459 and is composed ofD‐glucose,D‐mannose, andD‐glucuronic acid, in addition to acetic and pyruvic acids. Different amounts of pyruvic acid ketal are found in various preparations which can influence the viscosities of dilute xanthan solutions. Polysaccharide production on synthetic media was studied in small‐scale fermentors. Fermentation conditions were established for production of both high and low pyruvic acid gums (about 4 and 2% pyruvic acid, respectively). Low nitrogen [0.1% (NH4)2HPO4] and air (0.25 vol/liter/min) levels favor production of low pyruvate gum; increasing (NH4)2HPO4to 0.15%, adding K2HPO4, and increasing the air flow to 1.5 vol/liter/min favored production of normal gum. Both processes gave xanthan yields of 50 to 60%, based on 2.5% initialD‐glucose substrate, in two to three days. Differences in pyruvic acid content and in the quantity of gum produced under a given set of conditions were attributed to strain variability. Substrains were isolated that have desirable characteristics for production of xanthan gum; i.e., the ability to give good yields of high‐pyruvate gum when grown on both complex and sy

ISSN:0006-3592    

DOI:10.1002/bit.260200703

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe feed value of annual ryegrass straw was improved by treatment with various concentrations of NaOH or NH3followed by fermentation of the treated straw with a mixed culture ofCellulomonassp. andAlcaligenes faecalis. Laboratory feeding trials with voles showed that NaOH or NH3treatment considerably increased the feed efficiency of straw, but apparently gave a poorly palatable product. Fermentation tended to decrease thein vitrorumen digestibility (IVRD) of alkali‐treated straw. The fermentations were carried out aerobically on a semisolid straw matrix having 11–86% moisture. Treatment by both NaOH and NH3increased the IVRD of straw. NH3also increased the nitrogen content in straw. The optimum condition for alkaline treatment of the straw was 4–6% NaOH for 1 hr or with 3% NH3for four weeks at room temperature. A minimum of 63% moisture was needed for significant fermentation of the straw. The combined effects of NaOH treatment and fermentation more than doubled crude protein, doubled crude fat, and increased IVRD by 75%. The NH3plus fermentation treatment tripled crude protein, doubled crude fat, and increased IVRD by 60%. Acetic acid was the main volatile fatty acid in the fermented

ISSN:0006-3592    

DOI:10.1002/bit.260200704

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractFusarium moniliformewas grown on a carob aqueous extract in a chemostat for fungal protein production. The substrate was adjusted to provide 0.5% carob sugars supplemented with inorganic salts. The dilution rate varied from 0.086 to 0.227 hr−1under constant conditions of temperature (30°C), pH (4.5), and oxygen saturation (60–80%). A yield of 0.709 g dry mycelium/g consumed carob sugar and a productivity value of 0.687 g dry mycelium/liter hr−1were obtained at μ = 0.205 hr−1. The maintenance coefficient was 0.077 g carob sugar/g dry mycelium hr−1. While the carbohydrate and purine content of dry mycelium increased at μ values from 0.114 to 0.205 hr−1both true (Lowry) and crude (N × 6.25) protein contents decreased at the same μ range. Maximum values of 36.3% true and 47.9% crude protein of dry mycelium were obtained at μ = 0.114 hr−1, whereas a minimum purine content of 99.8 μmol/g corresponding to 6.42% nucleic acids was recorded at μ = 0.086 hr−1. It was concluded that a continuous fermentation of carob aqueous extract usingF. moniliformeshould be operated at growth rates of approximately 0.205 hr−1in order to ma

ISSN:0006-3592    

DOI:10.1002/bit.260200705

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractContinuous processing has been applied to human plasma fractionation by the cold ethanol process. On‐line pH control of ±0.05 pH units, flow control of ±1%, and temperature control of ±0.5°C have been achieved. Optimization of precipitation pHs has been carried out for purifying plasma protein fractions and albumin. During precipitation, the irreversible nature of the pH overshoots has been demonstrated. Compared to the batch processing mode, the continuous scheme produces an increased yield between 6 t

ISSN:0006-3592    

DOI:10.1002/bit.260200706

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractTrichoderma reeseiQM 9123 has been grown in batch culture in a 10 liter stirred fermentor, at a temperature of 30°C and pH 4.0. The fermentor was operated at a single stirrer speed of 400 rpm and air rate of 1 v/v/m. The effect of four inoculum sizes (0.5, 1.0, 3.0 and 5.0%) on the growth pattern and the aeration profiles was examined. Logarithmic growth of the fungus was observed. The aeration profile changed with inoculum size and at 5.0%, it was found that the oxygen uptake rate was controlled by the oxygen supply rate, during which the oxygen tension was zero

ISSN:0006-3592    

DOI:10.1002/bit.260200707

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractEleven species of fungi representative of a broad range of cell‐wall compositions were evaluated with respect to their papermaking potential as additives to woodpulp furnishes. Some of these species were also examined for their ability to grow on a spent liquor from the pulp‐and‐paper industry. Handsheets with various levels of incorporated mycelia exhibited a wide range of species‐dependent properties. Behavior of the mycelia in the sheets can be modified to a degree by physical and chemical treatments. The overall results suggest that small amounts (5–10% of the sheet constituents) of mycelia, grown inexpensively on waste effluents, might be incorporated into wood fiber paper without serious deleterious effects on paper strength properties. In some cases improved paper is obtained, and larger quantities of mycelia might be used to impart specific properties to th

ISSN:0006-3592    

DOI:10.1002/bit.260200708

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe stability of immobilized preparations of xanthine oxidase and urate oxidase was studied, and optimized, because of the potential joint use of both enzymes in clinical analysis. Xanthine oxidase was immobilized on cellulose, Sepharose, hornblende, Enzacryl‐TIO, and Porous glass. The half‐lives of these preparations at 30°C ranged from 40 min to 5.0 hr. In this respect immobilized enzyme resembled soluble enzyme in dilute solution (0.11 mg/ml), when the half‐live was about 3.5 hr. More concentrated enzyme solution (1 mg/ml), had a half‐life of 64 hr, and was, therefore, considerably more stable than the untreated immobilized xanthine oxidase preparations. Inclusion of albumen in storage and assay buffer increased the half‐life of bound xanthine oxidase. So also did treatment with glutaraldehyde: in the case of xanthine oxidase bound to Enzacryl‐TIO such treatment increased the half‐life at 30°C from 3 hr to about 100 hr. Immobilized xanthine dehydrogenase was more stable than immobilized xanthine oxidase: the dehydrogenase lost no activity during continuous assay for 5 hr at 30°C. The stability of immobilized urate oxidase depended on the quantity of enzyme used and on the time of stirring during immobilization: thus a preparation was made (by stirring urate oxidase (48 mg/g support) with Enzacryl‐TIO for 24 hr) which lost no activity dur

ISSN:0006-3592    

DOI:10.1002/bit.260200709

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260200710

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260200711

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY