Optimization Processing Parameters for Curcuma xanthorriza Oleoresin Yield and its Antioxidant Activity
Pages 97-102
Zarani M. Taher and Mohamad R. Sarmidi

DOI: http://dx.doi.org//10.6000/1927-3037.2015.04.03.3

Published: 01 December 2015

Abstract: Processing is a critical aspect of herbal based products, and processing method is known to affect the content, activity and bioavailability of bioactive compounds. Extraction of oleoresin from Curcuma xanthorriza is effected by several processing parameters. Appropriate solvent selection such as polar solvent result in better extraction yield while lower polarity solvent end up with extracts having higher concentration of active compounds. In this study, different processing parameters were carried out including blanching treatment (boiled, steamed) at range of time (24 hours, 48 hours and 72 hours), solvent of extraction (methanol, ethanol and acetone). The curcuminoid content and antioxidant activity were determined in Curcuma xanthorriza oleoresin. The result obtained was proved that ethanol was the most effective solvent. Blanching treatment affects the yield of oleoresin and promotes the release of curcuminoids content.

Production and Immobilization of Halophilic Invertase Produced from Honey Isolate Aspergillus niger EM77 (KF774181)
Pages 36-45
Mona Abdeltawab Esawy, Amany Lotfy Kansoh, Zeinab Hassan Kheiralla, Hala Abd Elmonem Ahmed, Tarek Aly-Kamal Kahil and Eman Karam Abd El-Hameed

DOI: http://dx.doi.org/10.6000/1927-3037.2014.03.02.1

Published: 22 July 2014

Abstract: Honey isolate Aspergillus niger EM77 was a good halophilic invertase producer in the presence of wheat bran as a complete medium (114.55 U/g), using solid state fermentation technique. Different parameters influence the enzyme productivity such as different pH values, temperature, incubation period, nitrogen and carbon sources were investigated. The optimum pH, temperature and incubation period for enzyme production were 5.5, 30^oC and 72 hrs, respectively. Sucrose at 2 % was more suitable carbon source for invertase production (144.39 U/g) and (NH₄)₂SO₄ at 0.15 % was the ideal nitrogen source. Among different metals ions MnSO₄ enhanced the enzyme productivity than other tested ions to 194.71 U/g. The partially purified enzyme was successfully entrapped in polyvinyl alcohol sponge shielded with agar starch layer (PVAsp Gs) and achieved 71% immobilization yield. The optimum conditions for immobilization were: pH 5.2, an incubation time of 15 min and a protein concentration of 250 mg/ml. Immobilized enzyme was reused 12 times with 29% activity loss. The free enzyme lost its activity completely at 70˚C after 45 minute and the immobilized form retained 80% of its activity at the same condition.The free and immobilized form reported extreme halophilic property since the highest enzyme activity was obtained between 3.5- 5 M.

Production and Characterization of Phospholipases C from some Bacillus thuringiensis Isolates Recovered from Egyptian Soil
Pages 10-24
Nooran Sherif Elleboudy, Walid Faisal ElKhatib, Mohammad Mabrouk Aboulwafa and Nadia Abdel-Haleem Hassouna

DOI: http://dx.doi.org/10.6000/1927-3037.2016.05.01.3

Published: 02 March 2016

Abstract: Two hundred and thirty one isolates, with the characteristic morphology of Genus Bacillus, were recovered from 100 soil samples collected from 7 different Egyptian governorates, and were screened for phospholipase C (PLC) production by egg-yolk plate method. Sixty isolates have shown very high PLC production and were further assessed using chromogenic assay method. The highest five producers, identified by 16S rRNA gene sequencing as Bacillus thuringiensis, were selected and their PLCs were purified to homogeneity using ammonium sulfate precipitation and Sephadex G-75 gel filtration chromatography. PLCs had molecular masses of 28.5 kDa as indicated by SDS-PAGE. The characteristics of the studied five PLCs were having maximal activities at 35-45°C and pH 7.2. The enzymes could retain more than half of their maximum activities at 30-60°C and pH 7-8. Equivalent activities were recorded at low water tension. PLC from B. thuringiensis KT159186 was relatively thermostable with a maximum activity at 40°C. The half-inactivation temperature was above 50°C, which compared favorably to that of other enzymes. Activity at the wide temperature range (20-80°C) was high (about 50% of maximum),. This PLC could tolerate pH as high as 12 with only 30% loss of activity. Specificity pattern of PLC from the same isolate showed equivalent activities toward phosphatidylcholine and phosphatidylinositol in addition to marked activity toward phosphatidylethanolamine, which makes it a typical non-specific PLC for industrial purposes. In conclusion, these characteristics of PLC from the test isolate make it attractive for various industrial applications.

Production of Bioagent for Calcium-Based Biocement
Pages 60-69
Viktor Stabnikov

DOI: http://dx.doi.org/10.6000/1927-3037.2016.05.02.5

Published: 12 August 2016

Abstract: Biocements and biogrouts are developing extensively as new materials alternative to cement and toxic chemical grouts. The most popular type of biocement is a mixture of urease-producing bacteria, urea and calcium salt. Thus, development of biotechnology to produce biomass of urease-active bacteria for large-scale biocementation is an important biotechnological task. Two strains of urease-producing bacteria, Yaniella sp. VS8 and Bacillus sp. VS1 that synthesized inducible and constitutive urease, respectively, were used in the present study. It was shown that low cost biomass of urease-active bacteria can be produced from the hydrolyzed excessive activated sludge of municipal wastewater treatment plant. The biomass of Yaniella sp. VS8 grown in this medium diminished the hydraulic conductivity of sand from 4.8×10^-4 m/s to 5∙10^-8 m/s after severalbiotreatments with solution of 1.5 M urea and 0.75M СаCl₂.