Stabilization of cetyltrimethylammonium bromide permeabilized yeast whole cell lactase

Summary Cetyltrimethylammonium bromide-permeabilized cells ofK. fragilis loose -galactosidase activity due to leaking of the enzyme into the medium. This leakage of the enzyme can be prevented by storing the permeabilized cells either in buffer containing 50% glycerol or by treating the permeabilized cells with 0.2% glutaraldehyde at 4°C for 10 min. In repeated batch hydrolysis of lactose in milk, glutaraldehyde treated cells could be repeatedly used very efficiently.     

Immobilization and stability of the NAD-dependent hydrogenase from alcaligenes eutrophus and of whole cells

Summary The purified soluble NAD-dependent hydrogenase from Alcaligenes eutrophus was immobilized to porous glass beads according to the glutaraldehyde method retaining about 80% of its original activity. Entrapment of the purified hydrogenase in photo-crosslinkable prepolymers led to apparent activity yields of 10–80% dependent on the thickness of the gel film. The storage stability of entrapped hydrogenase (t/2 = 4 d) was considerably lower than that of glass-bound hydrogenase (t/2 = 150 d). During continuous production of NADH (turnover conditions), the half-life of entrapped hydrogenase was not longer than 10 h. Whole cells of A. eutrophus entrapped in a polyurethane matrix were used to produce NADH with hydrogen gas as electron donor. After 18 runs for 4h each and storage periods overnight the residual activity was still about 50%.     

Cellulose acetate entrapment of Escherichia coli on cotton cloth for aspartate production

Summary Aspartase containingEscherichia coli cells were entrapped in cellulose acetate aggregated on cotton cloth. The enzyme activity of the cloth was stabilized by treatment with polyethylenimine and alkaline glutaraldehyde in the presence of 0.1 M sodium dithionite. A column packed with the cloth segments catalyzed 100% conversion of 1 M ammonium fumarate to aspartic acid at a space velocity of 7/h. When the same cloth segments were stirred at 100 rpm in the substrate solution, the productivity of the cloth increased 2.5 times.     

Degradation of limonin by entrappedRhodococcus fascians cells

Summary Limonin degradingRhodococcus fascians was immobilized by entrapment in alginate, k-carrageenan, agarose and polyacrylamide gels. Except this latter, gels were used both with and without polyethyleneimine treatment followed by glutaraldehyde crosslinking. Coated derivatives showed lower activity and stability and higher diffusional limitations that uncoated ones. Immobilized cells in k-carrageenan gave, globally, the best results.     

Immobilization of glucoamylase on naphthyl cotton cloth

Summary Aspergillus niger glucoamylase was adsorbed to -naphthyl cotton cloth by hydrophobic interaction. The adsorbed enzyme was cross-linked with glutaraldehyde. The immobilized glucoamylase exhibited greater pH dependence though the optimal pH did not change. The immobilized glucoamylase in a packed bed column completely hydrolysed 5% soluble starch at a specific velocity of about 4. Used naphthyl cloth could be regenerated by heating in 2 N NaOH at 100°C for 1 hour.     

Fructose production from Jerusalem artichoke by inulinase immobilized on chitin

Summary Inulinase fromAspergillus ficuum was immobilized by cross-linking with glutaraldehyde on chitin. Batch and continuous production of fructose from Jerusalem artichoke tuber was studied using this immobililized inulinase. In a batch reactor, the extent of hydrolysis attained 90% (D-fructose/D-glucose :86/14) in 10h and 77.5g/L of D-fructose was produced from the Jerusalem artichoke tuber juice. In a continuous packed bed column reactor, the maximum volumetric productivity of 61 g/L, h was obtained at residence time of 0.9h and conversion yield of 55%. At a fixed residence time of 2.6 h and 40° C, this could be operated for over two weeks with only a slight loss of activity (4.8%).     

Non-polluting wood and pulp delignification: Biomimetic ligninase system

Summary We report the delignification ofPinus radiata D Don,Eucalyptus globulus andEucalyptus grandis woods (formic acid treated and untreated) by 2 h treatment with a hemin/hydrogen peroxide system. The untreated chips and sawdust ofE. globulus were 30% and 50% delignified respectively. No significant effects were found forP. radiata sawdust;P. radiata treated chips (organosolv pulp) did not show any further delignification upon hemin/peroxide action, 25% delignification was achieved in untreated chips. In the case ofE. grandis untreated wood the delignification was better in sawdust than in chips, but in smaller percentage than in the otherEucalyptus species. This relation is maintained in substrates, treated with formic acid or untreated. The delignification of chips in both species ofEucalyptus was improved when they were pre-treated with formic acid. The loss of lignin in theE. grandis andE. globulus sawdust (pre-treated with formic acid) was 79% and 75% respectively.     

Fermentation of starch to ethanol by a complementary mixture of an amylolytic yeast andSaccharomyces cerevisiae

Summary Synergistic coculture of an amylolytic yeast (Saccharomycopsis fibuligera) andS. cerevisiae, a non-amylolytic yeast, fermented unhydrolyzed starch to ethanol with conversion efficiencies over 90% of the theoretical maximum. Fermentation was optimal between pH 5.0 to 6.0. Using a starch concentration of 10% (w/v) and a 5% (v/v) inoculum ofS. fibuligera, increasingS. cerevisiae inoculum from 4% to 12% (w/v) resulted in 35–40% (w/v) increase in ethanol yields. Anaerobic or limited aerobic incubation almost doubled ethanol yields.     

Plant regeneration from cultured cell-derived protoplasts of Pelargonium aridum,P. x hortorum and P. peltatum

Cultured protoplasts from cell suspensions of Pelargonium aridum, P.x hortorum and P. peltatum divided and formed callus. On agar-solidified regenerative medium, such protoplast-derived calli (p-calli) underwent plant regeneration at frequencies approaching 100% for P. aridum and 10% for P.x hortorum. Under similar conditions shoot primordia arose in 5% of P. peltatum p-calli, but these never developed into normal shoots. However, following a liquid-shake culture regime, whole plants were induced in 20% of P. peltatum p-calli. This approach also improved regeneration of P.x hortorum to 60%.Abbreviations NAA napthaleneacetic acid - 6-BAP 6-benzylaminopurine     

Electron flow shift inClostridium acetobutylicum fermentation by electrochemically introduced reducing equivalent

Electrochemical energy as a source of reducing equivalent was applied to the cultures ofClostridum acetobutylicum to understand the effects of the pressure by reducing equivalent on anaerobic bacteria. The fermentation byC. acetobutylicum with methyl viologen and electrochemical energy produced more butanol (up to 26%) than the control culture, whilst less acetone (up to 25%) was produced. But no effect was observed on the growth of the culture. These results were indirectly supported byin vitro electrochemical reduction of NAD⁺ and artificial electron carriers.     

Synthesis of novel sugars,oligoglucosyl-inositols,and their growth stimulating effect forBifidobacterium

Summary Novel sugars, oligoglucosyl-inositols, which were synthesized using CGTase fromBacillus ohbensis, stimulated the growth ofBifidobacterium. The enzyme catalyzed transglucosylation from -1,4-maltodextrin (donor) tomyo-inositol (acceptor). Of donors examined, -cyclodextrin gave superior oligoglucosyl-inositol yield of 56.6% (w/w) based on the conversion ratio of incubated inositol. Maltosyl-inositol stimulated growth ofB. adolescentis by 194% when compared with glucose.     

Preliminary screening of some fungal strains for protein upgrading of sugar-beet pulp

Summary Fourteen fungal strains were grown on sugar-beet pulp (SBP) in a semisolid state with the view of evaluating their capabilities in increasing the protein content of SBP. The highest increases were obtained withSporotrichum thermophile no 89 Paprican andThielavia terrestric ATCC 38088, which gave a protein content of 14.6% and 13.4% respectively after a 3-day culture or a net increase of 48% and 36% respectively over that of the unfermented SBP.     

Sucrose syrup from carob pod

Summary The ripe carob pod (pericarp) is rich in water-soluble sugars, mainly sucrose (63% on total sugars). Sucrose crystallization from aqueous carob extract is prevented by its reducing sugar content. The selective consumption of these sugars by mixed culture ofRhizopus oligosporus andSaccharomyces rouxii gives a sucrose syrup suitable for several uses e.g. sucrose extraction.     

A Simple,Preparative Procedure for N 3-Anisoyluridine and O 6-Diphenylcarbamoylguanosine 2′-O-(Tetrahydropyran-2-YL) Derivatives via The Corresponding 3′,5′-Dibenzoates

Abstract

3′,5′-Di-O-benzoyl-2′-O-(tetrahydropyran-2-yl)uridine and 3′,5′ -di-O-benzoyl-N ²-isobutyryl-2′-O-(tetrahydropyran-2-yl)guanosine are converted into-N ³-anisoyl-2′-O-(tetrahydropyran-2-yl)uridine (less and more polar diastereoisomers in 37% and 42% yields, respectively) and O ⁶-diphenyl carbamoylN ²-isobutyryl-2′-O-(tetrahydropyran-2-yl)- guanosine (less and more polar diastereoisomers in 15% and 59% yields, respectively), respectively, by N ³-anisoylation and O ⁶-diphenylcarbamoylation, followed by 3′,5′-di-O-debenzoylation.     

Ethanol production by Zymomonas mobilis CP4 from sugar cane chips

Summary The fermentation of large sugar cane chips (1.0–1.5 in) to ethanol by Zymomonas mobilis CP4 (Z. mobilis) was studied in two glass fermentors operating with culture circulation for agitation (the EX-FERM type): a. A laboratory scale(2.5 liter) cylindrical vessel; b. A bench scale (8 liter) wide vessel. Z. mobilis cultures consumed 89–96% of the cane sucrose, converting it to ethanol by 90–97% of the theoretical yield in the laboratory scale fermentor and by 83–90% in the bench scale fermentor culture. Comparative Saccharomyces spp. cultures in laboratory fermentor consumed 96–98% of the cane sucrose, with ethanol conversion of only 75–79% of the theoretical yield.These preliminary results indicated that sucrose in agricultural size sugar cane chips was ethanol fermentable as compared to small size sugar cane chips or to sugar cane juice. Z. mobilis CP4 cultures converted sucrose more efficiently to ethanol than Saccharomyces spp. as shown in the laboratory scale fermentor studies.The ethanol yields in a wide bench scale fermentor cultures were slightly lower than in a laboratory fermentor.     

Chitin synthesis inhibitors prevent cyst formation by Entamoeba trophozoites

Cysts of Entamoeba invadens obtained under axenic culture conditions have been reported to be similar to cysts of the human intestinal parasite E histolytica both in morphology and chitin presence in their wails. Mature E. invadens cyst forms, isolated from cultures following discontinuous Percoll gradient sedimentation were resistant (>80%) to detergent treatment. Addition of chitin synthesis inhibitors such as Polyoxin D and Nikkomycin (50 μg/ml) to cultures in encystation media markedly inhibited (>85%) the formation of detergent resistant cysts and prevented the incorporation of radiolabeled chitin precursor N-acetyl[³H]glucosamine. These findings suggest that chitin synthesis inhibitors may serve as drugs which specifically block the life cycle of the Entamoeba parasite.     

Kinetics of alcohol production by zymomonas mobilis at high sugar concentrations

Summary Studies on the growth ofZ.mobilis revealed that high concentrations of glucose (10-25%) can be efficiently and rapidly converted to ethanol in batch culture. By comparison withS. carlsbergensis,Z.mobilis had specific glucose uptake rates and specific ethanol productivies several times greater than the yeast.Z.mobilis also had ethanol yields of up to 97% of a theoretical value.     

Selection of yeast able to produce ethanol from glucose at 40° C

Summary A total of 55 yeast strains selected from 7 genera known to ferment carbohydrates to ethanol were screened for their ability to ferment glucose to ethanol in shaken flask culture at 37°, 40° and 45°C. Yields of more than 50% of the theoretical maximum were obtained with 28 strains at 37°C, but only 12 at 40°C. Only 6 could grow at 45°C, but they produced poor yields. In general Kluyveromyces strains were more thermotolerant than Saccharomyces and Candida strains, but Saccharomyces strains produced higher ethanol yields. The 8 strains with the highest yields at 40°C were evaluated in batch fermentations. Three of these, two Saccharomyces and one Candida, were able to meet minimum commercial targets set at 8% (v/v) ethanol from 14% (w/v) glucose at 40°C.     

The macromolecular composition and essential amino acid profiles of strains of Zymomonas mobilis

Summary From continuous culture studies it has been shown that the protein concentrations of strains of Z. mobilis (62–68%) were appreciably higher than for the yeast S.uvarum (45–50%). The DNA and RNA contents were similar for the two species. Comparison of the essential amino acids indicated that Z.mobilis did not exhibit the deficiency in methionine which was apparent in the yeast. Such a study of the macromolecular composition of cells of Z.mobilis is important in assessing its by-product nutritional value for animal feed supplementation.     

Transformation of white spruce and other conifer species byAgrobacterium tumefaciens

Studies of the ability ofAgrobacterium to transform white spruce (Picea glauca), Engelmann spruce (P. engelmanni), Sitka spruce (P. sitchensis) and Douglas-fir (Pseudotsuga menziesii) showed frequencies of gall formation from 0–80% depending upon the strain ofAgrobacterium, and the conifer species. Thirty sixA. tumefaciens strains and oneA. rhizogenes strain were tested on 6 month old white spruce seedlings. NineA. tumefaciens strains induced gall formation on more than 50% of the inoculated trees and at greater than 10% of the inoculated sites. One strain, B2/74 gave rise to galls at 28% of the inoculated sites on white spruce and induced the highest overall frequency of gall formation on all the conifer species tested. Relative frequency of gall formation was consistent among species, although the overall frequency was much higher on Douglas-fir. Of the well characterized strains for which disarmed derivatives are available only A281 (carrying the supervirulent tumor inducing plasmid, pTiBo542) gave efficient transformation. Stable integration of T-DNA encoded genes has been confirmed by the expression of opine synthesis and hormone autonomous growth. The transfer and long-term stable expression of kanamycin resistance and firefly luciferase activity using binary vector systems was also achieved.