摘要:

AbstractBacillus stearothermophilusAN 002 secreted thermostable alkaline amylase into a liquid growth medium containing 2 g/l starch. Amylase activity was highest at early stationary phase of growth. Among the various carbohydrates tested maximum amylase production was obtained with starch. When starch was replaced by other carbon sources, amylase production was reduced. Peptone and corn steep liquor (CSL) were the ideal nitrogen sources for amylase production by this strain. Of the phosphate sources tested, (NH4)2HPO4showed best restults. Amylase production was highest in a laboratory fermenter at a initial pH of 6.5 and at a constant pH of 7.0. The optimum aeration and agitation for amylase production were 0.66 v/v/m and 400 rev/min, respectively. Maximum growth was obtained at 55 °C and maximum amylase was produced at 50 °C. The amylase was found to be stable between pH 6.0 to 11.

ISSN:0233-111X    

DOI:10.1002/jobm.3620340302

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractA proximal segment ofB. subtilis sec Ygene was placed under the control of the induciblespacpromoter Lac repressor system. This fusion was integrated into the chromosomalspcoperon ofB. subtilisvia Campbell‐like reciprocal recombination. The growth of the resulting strain was strongly IPTG dependent. With staphylokinase and α‐amylase as reporter proteins it was found, that the protein secretion capacity of this strain was correlated to the conditions of repression or induction of the chromosomalspacprom

ISSN:0233-111X    

DOI:10.1002/jobm.3620340303

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620340304

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractMycobacterium phleiwas tested for its ability to utilize beet molasses as the sole carbon source and produce riboflavin. The crude beet molasses was analyzed and treated in various ways to reduce its heavy element content and to remove the muddy residue. Promising amounts of riboflavin were produced when the organism was cultivated on decationized (resin‐treated) beet molasses. The highest vitamin productivity was achieved by incubating the inoculated medium containing 9% molasses and initially adjusted to pH 6 under shacked condition for 6 days in the dar

ISSN:0233-111X    

DOI:10.1002/jobm.3620340305

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractResting phenol‐grown mycelia of the fungusPenicillium frequentansstrain Bi 7/2 were shown to be capable of metabolizing various monohalogenated phenols as well as 3,4‐dichlorophenol. 2,4.dichlorophenol could be metabolized in the presence of phenol as cosubstrate. In the first degradation step the halogenated phenols were oxidized to the corresponding halocatechols. Halocatechols substituted inpara‐position (4‐halocatechols) were further degraded under formation of 4‐carboxymethylenbut‐2‐en‐4‐olide. A partial dehalogenation took place splitting the ring system. 3‐Halocatechols were cleaved to 2‐halomuconic acids as dead end metabolites without a dehalogenation step. Dichlorophenols were only transformed to the corresponding catechols. In addition 3,5‐dichlorocatechol was O‐methylated to give two isomers of dichloroguaiacol. The halogenated catechols with the exception of 4‐fluorocatechol partly polymerized oxidatively in the culture fluid to form insoluble dark‐brown products. The degradation of halophenols are due to the action of unspecific intracellular enzymes responsible for phenol catabolism (phenol hydroxylase. catechol‐1,2‐dioxyg

ISSN:0233-111X    

DOI:10.1002/jobm.3620340306

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractOne hundred and fifty lactic acid bacteria (LAB) isolated from vacuum‐packaged processed meats were screened for antagonistic activity against various food spoilage microorganisms and foodborne pathogens. Nineteen strains produced bacteriocins active against closely related LAB andListeriastrains.Leuconostoc carnosum(LA54a and TA26b) andLeuconostoc mesenteroidessubspeciesdextrancum(TA33a) produced bacteriocins that were susceptible to proteolytic enzymes, but not to catalase, lysozyme or chloroform. They were heat stable up to 100 °C for thirty minutes at pH 2 to 7, and exerted a bacteriolytic effect. Bacteriocin production by allLeuconostocstrains was growth associated, occurring at incubation temperatures of 0 °C to 30 °C and initial medium pH 4.5 to 7.5. Probing of plasmid DNA from the threeLeuconostocstrains with an oligonucleotide probe homologous to the nucleotide sequence of leucocin A‐UAL 187 indicated plasmid‐mediated bacteriocin production. Homology of the threeLeuconostocbacteriocin‐coding genes to the amino‐terminal end of the leucocin A‐UAL 187 gene fromLeuconostoc gelidumUAL 187 is therefore suggested. This evidence implies that all threeLeuconostocstrains produce type 2,Listeriaactiv

ISSN:0233-111X    

DOI:10.1002/jobm.3620340307

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractArthrobacter oxydans317 capable of complete degradation of β‐sitosterol harbours two plasmids ‐pJLI and pRLI. Standard plasmid isolation methods can easily detect pJLI but not pRLI. The latter plasmid was isolated by a mild procedure using α,α′‐dipyridyl as lytic agent and separated from pJLI by agarose gel electrophoresis using the technique of electro elution into throughs. It's molecular weight was found to be about 3.5 kilo base (kb) pRLI was introduced into the plasmid curedA. oxydans317 AL. Through genetic transformation using protoplasts of the recepient strain, a transformant strainA. oxydans317 ALT bearing only pRLI plasmid was obtained. The transformant strain was unable to grow on 4‐androstene‐3, 17‐dione (AD) and 1,4‐androstadiene‐3,17‐dione (ADD) as sole carbon source but a modest growth was observed on 9α‐hydroxy‐4‐androstene‐3, 17‐dione (9α‐hydroxy AD) indicating the ability for steriod 1 (2)‐dehydrogenation and a lack of the capacity for α,α‐hydroxylation. The strain was able to form ADD from AD, and 1 (2)‐dehydrogenation of 3‐oxochol‐4‐en24‐oic acid from β‐sitosterol. Direct estimation of steroid (1 (2)‐dehydrogenase activity showed that the transformant strain and parent strain containing pRLI had high enzyme activity where as strains lacking in this plasmid had negligible enzyme activity. It was concluded that pRLI is resp

ISSN:0233-111X    

DOI:10.1002/jobm.3620340308

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractGrowth and urea regulation of heterocyst and nitrogenase formation have been studied in the diazotrophic cyanobacteriumAnabaena cycadeaeand its glutamine auxotrophic mutant strain lacking glutamine synthetase (GS) activity. The parent strain having normal GS activity utilized urea as sole nitrogen source without producing N2‐fixing heterocysts. In contrast, the mutant strain lacking GS activity could not utilize urea as sole nitrogen source although similar to the parent strain it lacked N2‐fixing heterocysts in urea‐medium. Both parent and mutant strain showed high levels of urea uptake and urease activity in the presence and absence of a GS inhibitor, l‐methionine‐dl‐sulphoximine (MSX). Urea‐dependent NH 4+production by MSX‐untreated cells was only confined to the mutant strain lacking GS activity whereas the parent strain having normal GS activity produced NH 4+only in the presence of MSX. These results suggest that (i) GS is the sole NH 4+assimilating as well as glutamine‐forming route in heterocystous N2‐fixing cyanobacteria; (ii) while GS activity is necessarily required for the assimilation of urea as sole nitrogen source, it is however, not required for the urea inhibition of heterocysts and nitrogenase formation; (iii) that NH 4+resulting from the hydrolysis of urea and not GS‐mediated pathway of NH 4+assimilation appears to be the initial repressor signal for heterocysts and nitrogenase formation; and (iv) GS does not control the formation of N2‐fixing heterocysts, urea u

ISSN:0233-111X    

DOI:10.1002/jobm.3620340309

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620340310

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY

摘要:

AbstractGrowth response of the planktonic cyanobacteriumMicrocystis aeruginosato various concentrations of the herbicides and pesticides viz. CuSO4, DCMU (analytical grade Diuron), Karmex (commercial grade Diuron), 2,4‐D, Fernoxone, BHC and bleaching powder (CCH) was studied in laboratory culture. The organism was sensitive to very low concentrations of CuSO4, DCMU and Karmex. Lethal concentration of Karmex and CuSO4were found to be 0.1 μg · ml−1and 5.0 μg · ml−1respectively. The cyanobacterium could tolerate the other chemicals tested up to a concentration of over 500 μg · ml−1. On culturing the organism in the CuSO4containing media, toxic effect of the chemical was reduced to a significant extent. This indicated that CuSO4was accumulated or detoxified in theMicrocystiscells. Toxic effect of Karmex on the organism was not reduced under similar experiment

ISSN:0233-111X    

DOI:10.1002/jobm.3620340311

出版商:Wiley‐VCH    

年代:1994

数据来源: WILEY