S534 Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576

[PUB-O.9]

Antioxidant Potential of Centella asiatica-Associated Endo-phytic Bacteria

Arash Rafat 1,∗, Koshy Philip 1, Sekaran Muniandy 2

1 Faculty of Science, University of Malaya, Malaysia2 Faculty of Medicine, University of Malaya, MalaysiaKeywords: Antioxidant Activity; Centella asiatica; endophytic bac-teria

Introduction: The scantly studied group of microorganisms ofplant endophytic bacteria may offer a great source of bioactivecompounds. In this study, some of the endophytic bacteria wereisolated from leaf and stem parts of Centella asiatica and identi-fied. The antioxidant potential of the isolated bacteria was thenevaluated.

Methods: Identification of isolated bacteria was carried outusing 16S rDNA method. Erythrocytes hemolysis protection,2,2–diphenyl-1-picrylhydrazil free radical scavenging and Cu++

reductive capacity assays were applied to determine the antioxi-dant activity of the cell free supernatant from the bacterial culturedbroth of the isolated endophytic bacteria.

Results: The C. asiatica-associated bacteria were identifiedas Methylobacterium radiotolerans, Bacillus gibsonii, Providen-cia vermicola, Xanthomonas perforans, Erwinia persicina, Pantoeaagglomerans, Erwinia persicina, Pseudomonas fulva. Pantoea agglom-erans followed by Erwina persicina showing the order of the highestprotection against rabbit erythrocytes hemolysis compared to pos-itive control (1 mg/ml acid ascorbic). The highest percentage of2,2–diphenyl-1-picrylhydrazil scavenging was also obtained fromPantoea agglomerans cultured broth but followed by Providen-cia vermicola. Both P. agglomerans and P. vermicola free radicalscavenging capacities were higher than positive control in thatexperiment (1 mg/ml BHT). Antioxidant reductive capacity assaywas in agreement with both erythrocytes hemolysis protectionand 2,2–diphenyl-1-picrylhydrazil free radical scavenging exami-nations about the antioxidant activity of P. agglomerans. The highestCu++ reductive capacity obtained from P. agglomerans compared tothe other isolated bacteria but it was less compared to the positivecontrol in this assay (1 mg/ml acid ascorbic).

Discussion: The study confirmed the value of the C. asiatica endo-phytic bacteria as a novel source of antioxidant compounds. Furtherstudies to evaluate the other possible bioactivities of the isolatedbacteria are suggested.

doi:10.1016/j.jbiotec.2010.09.870

[PUB-O.10]

Study of yeast sterols biosynthesis and their identification

Lahouassa Redha ∗, A. Guinak

Saint-Petersbourg State University of Technology (Technical Univer-sity), Russian FederationKeywords: Sterols; vitamin D; Saccharomyces cerevisiae; ergosterol

Vitamins are important compounds for human health. Specialrole is given to vitamins - ergosterol and calciferol, as well as theirderivatives [1]. Nowadays one of the actual problems in biotech-nology is finding new ways of obtaining the highest yield sterols[2]. Thus, the study of ergosterol biosynthesis mechanisms and itsderivatives in biotechnology is important.

The purpose of this study was to investigate the mechanismsof the biosynthesis of sterols mutant strains of Saccharomyces

cerevisiae with different enzymatic reactions and identification ofsterols fractions.

The aim of this work is to study the yeast sterols biosynthesisand their identification.

The objects of study are strains of Saccharomyces cerevisiaeyeast and their mutants.

Sterols were split of by the method of Brevik-Ovadsawith N.P. Mikhailova modification. Ergosterol and cholesterolwere measured by 1H and 13C RMN (DRX 500 Bruker),UV-spectrophotometry (UV-3000 Shimadzu) and gas-liquid chro-matography (Chrompack 9000 Varian). There were obtained andidentified the following sterol fractions: cholesta �8,24; �5,7,24;�5,7,22,24 and ergosta �8; �8,24(28);�5,7,22,24(28).

. It was identified that the ferments in these processes had dif-ferent substrate specificity.

It was shown that double bonds �24(28) were restored at almostall initial compounds.

Found that the activity of the enzyme 24 (28) methylreductasetowards cholesterol derivative is not due to the fact that the doublebond is in position 24.

Contents zimosterol in fractions up to 80% and 70% ofcholesta-5,7,24-trienol. The maximum concentration of cholesta-5,7,24-trienola achieved with sequential aeration.

Thus, there were isolated stable producers of sterols -such as ergosterol, fenosterol, zimosterol, ergosta-5,7-dien-3�-ol,cholesta-7,24-dien-3 �, 4,14-dimethylfecosterin, cholesta-5,7,24-triene-3�-ol and cholesta-5,7,22,24-tetraene-3�-ol selected opti-mal conditions for their formation, as well as regulativemechanisms of biosynthesis. 1. Katie M. Dixon, Rebecca S. Mason.Vitamin D / / The international Journal of Biochemistry and CellBiology. Vol. 41 (5), 2008 p. 982 - 985. 2. AI Orlov. Sterols. Biosyn-thesis and transformation. SPb., OOO Izdatel’stvo “OM-Press, 2004.P.144.

doi:10.1016/j.jbiotec.2010.09.871

[PUB-O.11]

Enhancement of biodemulsifier produced by alkaliphilic Alcali-genes sp. S-XJ-1 by pH optimization and waste edible oilsupplementation strategy

Jia Liu ∗, Xiang-feng Huang, Li-jun Lu, Dian-hai Yang, Qi Zhou

College of Environmental Science & Engineering, State Key Laboratoryof Pollution Control and Resource Reuse, ChinaKeywords: biodemulsifier; alkaliphilic; waste edible oil; fatty acidester

In the oil extraction industry, large amount of demulsifieris in great demand for destabilization of the crude oil emul-sion. Recently, environment-friendly biodemulsifier have becamea research focus of demulsifier. However, biodemulsifier have notbeen applied in the petroleum industry as its production cost washigher than chemical demulsifier which was commonly used inthe oilfield. In this study, a high efficient demulsifying strain ofAlicaligenes sp. S-XJ-1 was investigated on enhancement of itsbiosynthesis to decrease the cost. The impact of culture pH andwaste edible oil as substituted carbon source was proposed for thefirst time.

The results showed that strain S-XJ-1 was a faculta-tive alkaliphilic bacteria. With the increase of initial culturepH, biodemulsifier yield and demulsification performance wasincreased gradually. The yield of biodemulsifier can reach 3.55 g/Lwhen the optimal pH was set as 10. The mechanisms for S-XJ-1endured in alkaline conditions included the release of acidic sub-