enhancement of biodemulsifier produced by alkaliphilic alcaligenes sp. s-xj-1 by ph optimization and...

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-

Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576 S535

stances, enhancing the cellwall negative charge and the Na+/H+

antiporter mechanism. The optimal technique for use of waste edi-ble oils included two procedures: the initial pH of the culture wasset as 10 with 2%(v/v) paraffin as carbon source, after 4 day’s cultiva-tion, 2%(v/v) of waste edible oil was supplemented into the cultureand whole cultivation was ended on day 7. By adoption of thistechnique, biodemulsifier production was increased 68% comparedwith paraffin as sole carbon source. Characteristics of its use of fattyacid ester were analyzed as follows. Short-chain fatty acid esterwere preferred which can produce high yield of biodemulsifier butwith poor demulsification capability. Long-chain saturated fattyacid ester was more difficult to be utilized but the biodemulsifiersynthesized performed better demulsification capability. There-fore, waste edible oil rich of long-chain saturated fatty acid esterwas recommended as the optimal carbon source.

doi:10.1016/j.jbiotec.2010.09.872

[PUB-O.12]

Purification of lignin in black liquor by biotechnology

Lingxi Bu, Jie Lu, Ruifeng Yang ∗

Dalian Polytechnic University, ChinaKeywords: Black liquor; Lignin; Purification; biotechnology

After the degradation of carbohydrate with the biotechnology,the lignin in the black liquor can be purified. The lignin after purifi-cation can be used better, and the purification process can perfectthe liquid waste disposal process of the pulp and paper making, atthe same time it can prevent secondary pollution during the mul-tipurpose use of the lignin. Degrade the carbohydrate with somekinds of enzyme, and the measure the quantity of the reducingsugar in the black liquor.

The result shows that the complex enzyme is the best, and thehighest degradation rate of the sugar can reach 72.3%; Put theenzyme to the black liquor after the degradation of carbohydrate,the removal percent of the total sugar can get 75.6%; at the sametime, 802.1 ml alcohol can be got from the 1L black liquor afterfermentation; and the rate of lignin content in the organic mattercan be reached 76.4%, the rate of lignin precipitated from the blackliquor at pH 3 in the organic matter can be reached 86.1%. So thelignin had been purified to some degrees.

doi:10.1016/j.jbiotec.2010.09.873

[PUB-O.13]

Effect of degree of polymerization of lignocellulosic biomass oncharacteristics of enzymatic hydrolysis products for L-lactic acidproduction

Limin Chang, Jie Lu ∗, Ruifeng Yang, Changxin Zhao, Feiyu Zhang

Dalian Polytechnic University, ChinaKeywords: degree of polymerization; lignocellulosic biomass;enzymatic hydrolysis; L-lactic acid

Lignocellulosic biomass could play a greatly expanded role asa source of L-lactic acid in the future. Lignocellulosic biomass is alinear polymer of anhydroglucose units joined by �(1-4)linkageswith a degree of polymerization(DP)from 100 to 20000. DP is justone of the factors that limit enzymatic hydrolysis rates of ligno-cellulosic biomass. The effect of DP on characteristics of enzymatichydrolysis products for L-lactic production was investigated. Theprocess of L-lactic acid production yields different results when

the compositions of enzymatic hydrolysis products are different.The current study focused on gaining new insight into building therelation between DP and the composition of enzymatic hydroly-sis products. When the characteristics of products from enzymatichydrolysis are different, the process of L-lactic acid fermentationwill have change considerably.

Lignocellulosic biomass of different DP was obtained bymechanical grinding. The compositions of enzymatic hydrolysisproducts were analyzed by means of GC. The results showed thatdecreasing DP from 521 to 77 affected the contents of glucose,which increased from 5.31 g/L to 31.1 g/L, and 5.72 g/L xylose werereleased from lignocellulosic biomass.

Mechanisms that control xylan release with decreasing ofDP during mechanical grinding of lignocellulosic biomass wereexplored by FT-IR and UV. The explanation for these phenomenawas that lignin was removed and lignin-xylan compounds playan important role in the hydrolysis of lignocellulosic biomass. Theresults showed that the lower DP of lignocellulosic biomass, themore severe was the damage to cellulose high-level structure.Ether, glycosidic, and acetal bonds, as well as some other lignin-xylan complexes chemical binding were affected.

From the above results, when DP is very low, one can expect alot of xylose dissolution. Therefore, for L-lactic acid fermentation itis important to first select or modify DP of cellulose in the biomass.

doi:10.1016/j.jbiotec.2010.09.874

[PUB-O.14]

Characteristic of enzymatic hydrolysis of different morpholog-ical structure fractions of corn stalk

Yuifei Dong, Ruifeng Yang ∗, Jie Lu, Tengfei Yin

Dalian Polytechnic University, ChinaKeywords: Enzymatic hydrolysis; Morphological structure; cellu-lase

Bioconversion of corn stalk for production of high add-valuedchemicals is flourishing. However, most existing corn stalk utiliza-tion and most current disposal methods lack economic feasibility tojustify use of the material as a whole carbohydrate source. In orderto solve these problems, it is important to recognize the character-istic of enzymatic hydrolysis of different morphological structurefractions of corn stalk.

Corn stalk was divided into fractions by morphological char-acter, and the enzymatic hydrolysis of these fractions wasinvestigated. Chemical composition and the proportions of cellsof different compositions were very variable in different morpho-logical structure fractions. This has a fundamental effect on theenzyme adsorption capability and hydrolysis performance. Cellu-lase, �- glucanase and xylanase were added to the husks, leaves,pith and whole stalks of cornstalks, and the enzymatic hydrolysisof them was investigated.

The experiment results show the following optimum conditionsfor the enzymatic hydrolysis: pH 4.8, temperature 50 ◦C, hydrolysistime 48 h, and enzyme dosage 88FPU/g(cellulase) and 700FPU/g(�-glucanase). After that, the effection of enzymatic hydrolysis of dif-ferent morphological structure fractions of corn stalk by cellulase,�- Glucanase and xylanase was compared. We can see that the con-tent of sugar degraded by �- glucanase is the highest. And thenthe enzyme solution was analyzed by high-efficiency liquid chro-matography (HPLC), the result shows that there are some othercarbohydrate, such as xylose, besides a number of glucose, and thepentose. The results showed that the fastest hydrolytic rate andthe highest sugar content were obtained in the pith of corn stalks.