Books by khalid J K Luti
Antibiotics are complex organic compounds usually synthesized via many separate enzymatic steps t... more Antibiotics are complex organic compounds usually synthesized via many separate enzymatic steps through complex pathways which are normally energetically expensive. Why should microorganisms spend their energy producing these compounds unless they play a crucial role in their life cycle or survival in their natural habitat? Scientists believe that antibiotics are synthesized to give the antibiotic producing organism an advantage over any possible competing organisms. This chapter attempts to discuss the following question: is it possible to exploit interspecies interactions to create an effect on the antibiotic production pattern that may form the basis for producing more effective antibiotics. In this field, most research in the literature is focused on exploiting inter-species interactions to induce the unexpressed biosynthetic pathways for new bioactive compounds or to improve the productivity of the antibiotic-producing strains. In the pages that follow, an important aspect of inter-species interactions in the production of antibiotics will be argued that needs to be considered: this is the possibility of inter-species interactions to motivate the producer strains to choose their antibiotic “weapons” that would be more effective against the competitors when the producer strains have the capability to produce one or more than one antibiotic.
Papers by khalid J K Luti
Al-Khwarizmi Engineering Journal, 2018
Prodigiosin is a ‘natural red pigment produced by Serratia marcescens which exhibits immunosuppre... more Prodigiosin is a ‘natural red pigment produced by Serratia marcescens which exhibits immunosuppressive and anticancer properties in addition to antimicrobial activities. This work presents an attempt to maximize the production of prodigiosin by two different strategies: one factor at time (OFAT) and statistical optimization. The result of OFAT revealed that sucrose and peptone were the best carbon and nitrogen sources for pigment production with concentration of prodigiosin of about 135 mg/ L. This value was increased to 331.6mg/ L with an optimized ratio of C/N (60:40) and reached 356.8 with pH 6 and 2% inoculum size at end of classical optimization. Statistical experimental design based on Response surface methodology was conducted to optimize the composition of trace element. The design revealed that the predicted prodigiosin production of 406 mg/L can be achieved when concentrations of trace element CaCl2·2H2O, FeSO4·4H2O, MgSO4·7H2O and MnSO4·4H2O were equal to 9.22, 0.32, 0.67...
Antibiotics are complex organic compounds usually synthesized via many separate enzymatic steps t... more Antibiotics are complex organic compounds usually synthesized via many separate enzymatic steps through complex pathways which are normally energetically expensive. Why should microorganisms spend their energy producing these compounds unless they play a crucial role in their life cycle or survival in their natural habitat? Scientists believe that antibiotics are synthesized to give the antibiotic producing organism an advantage over any possible competing organisms. This chapter attempts to discuss the following question: is it possible to exploit interspecies interactions to create an effect on the antibiotic production pattern that may form the basis for either producing more effective antibiotics or increase their production. In this field, most research in the literature is focused on exploiting inter-species interactions to induce the unexpressed biosynthetic pathways for new bioactive compounds or to improve the productivity of the antibiotic-producing strains. In the pages t...
In the nature, microorganisms is found in populations of different species in which they interact... more In the nature, microorganisms is found in populations of different species in which they interact with each other. It is possible to hypothesise that microorganisms have acquired a diverse of physiological and metabolic responses as a result of inter-species interactions such as production of bioactive compounds. In fact, many of these reponses remain silent in the laboratory and hence many compounds which may be important are not appear. In this work, we utilized microbil interactions to activate silent pathways in order to induce metabolites production. Thirty different isolates of Streptomyces were examined for their pigment production in a pure and mixed cultures with Bacillus subtilis. In an interestng finding, we recognized a pink pigment produced by the isolate Streptomyces MR24 only in the mixed culture. The maximum absorption peak of the extracted pink pigment was approximately at 450 nm. The FT-IR spectra analysis revealed different stretching and bending functional groups...
Several studies have reported that some infections are resulted from distortions of microflora, a... more Several studies have reported that some infections are resulted from distortions of microflora, and hence, it was hypothesized that exploiting the defensive ability of normal flora may represent a promising approach to treat bacterial pathogens. This work seeks to bring attention to bacteriocin-producing bacteria that exist in the outer ear in order to exploit them to treat outer ear infections. Twelve bacterial isolates were collected from the outer ear of healthy individuals and subjected to a screening program in two steps: primary screening using agar plug diffusion assay to test the competitive activities against each other and secondary screening using well diffusion method. Staphylococcus epidermidis A3 showed an activity against different ear isolates with approximately 160 arbitrary unites (AU)/ml of bacteriocin activity. Tryptic soya broth was selected as the best medium to obtain maximum production of bacteriocin which showed a bactericidal action. In addition, 12 clinica...
Journal of Pure and Applied Microbiology
Biotechnology Letters, 2011
ABSTRACT An extracellular β-galactosidase from the thermophilic fungus Rhizomucor Pusillus IB8 ha... more ABSTRACT An extracellular β-galactosidase from the thermophilic fungus Rhizomucor Pusillus IB8 has been purified via several steps included precipitation by ammonium sulphate at 80 % saturation, DEAE- Cellulose Ion exchange chromatography and gel filteration on sepharose CL-6B column. The Final purification folds and the yield of the enzyme were 42.5 and 24.8 % respectively. The purified β-galactosidase has an optimum pH for its activity between 4.5 to 5, while the optimum pH for enzyme stability was between 5 to 5.5. Futhermore, it was found that the optimum temperature for its activity was 60 C°. The purified enzyme retained approximatly 98% of its original activity when incubated at 60 C° for 60 min. However, 25 % of its activity was lost when incubated for 120 min at the same tmperaure. Activation energy for conversion of the substrate ONPG to products was 6.15 Kcal / mol, whereas, for enzyme denaturation it was 99.3 Kcal / mol. The molecular weight of the purified enzyme was 232000 dalton as determined by gel filtration on sepharose CL-6B. Kinetic studies showed that the Michaelis constant (Km) and maximum velocity (Vmax) values for the purified enzyme using ONPG as a substrate were 0.46 mM and 223 μM /min respectively.
We report a strategy for exploiting quorum sensing molecules to elicit antibiotic production usin... more We report a strategy for exploiting quorum sensing molecules to elicit antibiotic production using a model bacteria Streptomyces coelicolor. The strategy was based on introducing an amount of spent culture supernatant from early stationary phase of Streptomyces coelicolor to its fermentation culture. The antibiotics studied were red-pigmented undecylprodigiosin and blue-pigmented actinorhodin. Investigations were performed in shake flasks and 2L bioreactor. Different amounts of spent culture supernatant ranging from 1 to 10% added at 0 time were used. For the test cultures, production of undecylprodigiosin was significantly increased by 2.2 -fold compared to the control cultures of S. coelicolor, whereas actinorhodin was increased by 1.6–fold. Furthermore, another positive outcome of this strategy was the earlier onset of antibiotics production by 24-48h compared to the control culture. Growth of S. coelicolor and glucose consumption of the test cultures were also studied and compar...
Biotechnology Letters, 2011
Biochemical Engineering Journal, 2011
Applied Microbiology and Biotechnology, 2011
Biotechnology Letters, 2011
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Books by khalid J K Luti
Papers by khalid J K Luti