Day 3 :
- Track 4: Microbes In Aquaculture
Track 5: Microbes In Beverages Industry
Track 9: Microbial Metabolites
Track 10: Environmental Microbiology and ecology
Session Introduction
Marguerite DOLS-LAFARGUE
Bordeaux National Polytechnic Institute, France
Title: Polysaccharide production by wine lactic acid bacteria : negative trait or potential advantage ?
Biography:
M. DOLS-LAFARGUE has completed his PhD at the age of 25 years from INSA Toulouse (France). She is Professor of Biochemistry at Bordeaux National Polytechnic Institute.
Abstract:
Wine lactic acid bacteria (Lactobacillus, Pediococcus, Leuconostoc and Oenococcus) generally multiply after alcoholic fermentation and consume the elements left by the yeast (sugars, acids). They drive the malolactic fermentation (MLF) which improves the taste and overall quality of wine. Despite the accumulation of knowledge, MLF is still a difficult step in the winemaking. Selected malolactic starter cultures have thus been developed. According to their characteristics, they can be introduced into the wine at the end or during alcoholic fermentation, but implantation failures are still frequent: MLF may be initiated by the starter, then stopped or led by the native flora, with the risk that the dominant native strains induce beverage alteration. On the other hand, several wine lactic acid bacteria, especially Pediococcus parvulus and Oenococcus oeni, have been described exopolysaccharides producers. O. oeni is the bacterium that most frequently performs MLF in temperate areas, while P. parvulus is rather considered an agent of alteration, because many strains cause wine ropiness. This alteration is linked to the accumulation of ï¢-glucan in the wine. The polymer synthesis is catalyzed by a glucosyltransferase Gtf, encoded by the gtf gene. A detailed study has shown that this gene fairly widespread among wine lactic acid bacteria. Besides, in O. oeni, many other genetic determinants associated with the production of exopolysaccharides have been identified and associated with more "discrete" phenotypes. Instead being detrimental to wine quality, these polymers may, in the future, being valued in several ways: (i) their presence may allow the development of more robust malolactic starters and (ii) from the organoleptic point of view, the wines naturally containing polysaccharides often display decreased astringency and increased fullness, body and round sensation.
Zhigang (Peter) Zhou
Chinese Academy of Agricultural Sciences, China
Title: The probiotic effector molecules in Lactobacilli and their action mechanism: A review
Biography:
Prof. Zhigang Zhou has completed his PhD at the age of 28 years from Institute of Hydrobiology, Chinese Academy of Sciences and postdoctoral studies from Shantou University. He is the director of Department of Aqua Nutrition and Feed, Feed Research Institute of CAAS with the subject “fish gut microbe”. He has published more than 60 papers in reputed journals.
Abstract:
The mechanism underlying the variety of health benefits of probiotic Lactobacillus remains poorly understood (Marco et al., 2006). During the last decade, a substantial body of scientific evidence has accumulated suggesting that certain surface-associated and extracellular components produced by Lactobacillus could be responsible for some of their mechanisms of action. They are thought to play essential roles in the molecular intercommunication between host-bacteria, and in the monitoring of the bacterial environment (van Pijkeren et al., 2006). In Lactobacillus, these probiotic effector molecules could be responsible for some of probiotic traits, such as pathogen inhibition and immunomodulation (Buck et al., 2005), and it is urgently to exploit more probiotic effector molecules in order to have a better understanding of how commensal, probiotic, and pathogenic microorganisms interact with one another and the mammalian host. In this presentation, we systematically review the most interesting aspects of probiotic effector molecules derived from genera Lactobacillus. Additionally, the potential mechanisms of specific probiotic effector factors and the responses they can induce in the host will also be discussed. We also wish to provide some insights for further elucidation of microbe-microbe and microbe-host interactions involved in the probiotic effects of Lactobacillus at the molecular and cellular levels.
LuÃs E. Trujillo
Universidad de las Fuerzas Armadas , Ecuador
Title: A genetically modified Pichia pastoris-based biocatalyst for short-chain FOS production from sucrose
Biography:
Dr Luis Enrique is currently working as Assoc Prof in Universidad de las Fuerzas Armadas , Ecuador
Abstract:
The methylotrophic yeast Pichia pastoris is not a saccharolityc yeast so, it has become in an important host organism for the high level production of recombinant enzymes that use sucrose as substrates. We have developed a yeast based- biocatalyst for massive conversion of sucrose into fructooligosaccharides (FOS), particularly the commercially most attractive 1-kestose (GF2). These compounds are highly demanded as prebiotics in the functional food market so, the gene encoding a native plant sucrose:sucrose 1-fructosyltransferase (1-SST) able to produce vast amounts of FOS from sucrose, was expressed constitutively in Pichia pastoris. Secretion driven by the S. cerevisiae alpha-factor signal peptide resulted in periplasmic retention (30%) and extracellular release (70%) of the recombinant enzyme. The gradual increase of the transgene dosage from one to nine integrated copies proportionally enhanced 1-SST yield to an overall activity of 140 U/mL without causing toxicity to the yeast cells. The acquired ability to utilize sucrose allowed the transgenic yeast to reach high biomass values (above 370 g wet weight / L) at relatively low costs in fed-batch fermentations for 72 h. Intact cells were entrapped in calcium alginate beads and shown to yield high FOS levels (55-60% of carbohydrates in the reaction mixture) in concentrated reactions (initial sucrose 50ºBx) at pH 5.5-6.0 and 30-40ºC. Sucrose hydrolysis was negligible and the 1-kestose content (90% of total FOS) was three-fold higher than the values reported with current fungal systems. In terms of productivity and stability, the immobilized cells (1 kg) produced 2.5 kg FOS per day and retained 90% of its original activity after 20 cycles of continuous reuse at 30ºC. The biocatalyst offers flexibility of operation in packed-bed, batch or continuous-flow stirred tanks reactors. This genetically modified yeast allow the industrial production of FOS in a cost effective manner.
Imane Wahby
MAScIR, Morocco
Title: Microalgae for industrial applications: from laboratory to industry
Biography:
Imane Wahby has completed his PhD at the age of 28 years from Granada University and postdoctoral studies from CSIC. She is the director of Green Biotechnology Center in MAScIR (Morocco) working on the valorization of natural resources. She has 4 papers published and 8 patents related to the industrial application of microalgae. She led more than 10 projects for industrial application of microorganisms mainly in the field of agriculture, alimentation and cosmetic.
Abstract:
Microalgae represent an emerging biological resource of great importance for its potential applications in different fields, in particular as a new source of valuable nutrients and biologically active molecules. MAScIR works since 2010 on a global project for microalgae valorization and developed a microalgae collection fully characterized (lipids, FAMEs profile, proteins, biological activities, etc.). Four projects are ongoing to develop products for agriculture and ingredients for neutraceutic and cosmetic use. Indeed microalgae with high content of amino acids, nitrogen, phosphorus and phytohormons was used to formulate a liquid product used as biofertiliser/growth booster developed with an industrial partner operating in biological agriculture. Other microalgae, mainly belonging to Arthrospira and Isochrysis genius, showed highest polysaccharides content and are used to formulate anti-stress products for agriculture. Developed formula allowed plants growth in highly saline soil and increased plant immunity against some bacterial and fungal disease (Botrytis and Clavibacter). For neutraceutical application, some microalgae showed high content of PUFA, iron and proteins (70% DW) and are used to develop a new formula containing high PUFA content coupled with two active extracts, actually in pre-commercial phase. Development of pharmaceutical ingredients from microalgae for cosmetic application is also targeted, a newly developed formula showed an anti-acne activity combining: bacteriostatic effect against the two bacteria responsible of the acne: Propionibacterium acnes and Staphylococcus epidermidis, anti-inflammatory and antioxydant effect and skin cell regenerative effect for an integral treatment of the acne. The bridge between R&D and industrial scale will be discussed for each project.
Ahmed Idris Hassen
Plant Protection Research Institute, South Africa
Title: Members of the Genus Bradyrhizobium are the major nodulating microsymbionts of indigenous and exotic forage legumes in South Africa
Biography:
Ahmed Idris Hassen has completed his PhD in 2007 at the age of 38 years from the Univeristy of Pretoria and postdoctoral studies from the Department of Microbiology and Plant Pathology, Univeristy of Pretoria, South Africa. He is a senior researcher in Applied Microbiology and curator of the South African Rhizobium Culture Collection (SARCC) hosted by the Agricultural Research Council (ARC) Plant Protection Research Institute. He has published 9 papers in reputed journals and has been serving as an editorial board member of the Journal of Applied and Environmental Microbiology, Science and Education Publishing, USA and editorial member of the Research and Communications in Biological Science, JYOTI Academic Press, and the Netherlands.
Abstract:
The nodulation screening and characterization of rhizobial microsymbionts of selected forage and pasture legumes was conducted following the Koch’s postulate experiment under glasshouse condition. The authentication test involved the use of rhizobial strains previously collected from the legumes Macrotyloma axillare, Desmodium uncinatum, Indigofera spicata var. spicata, Stylosanthus gracillis, Vigna unguiculata and Vigna sp. The results revealed that all the tested strains of rhizobia showed effectiveness in nodulating their respective legume host from which they were initially isolated with statistically significant (p= 0.05) increase in plant biomass and nodule number in comparison with the un-inoculated control. To elucidate their identity and phylogenetic relatedness, the most effective strains were selected and characterized using the 16S rRNA sequence analysis. The analysis confirmed that the majority of the strains associated with the nodulation of the forage legumes belong to the Genus Bradyrhizobium with a 99% similarity in their 16S rRNA. The results obtained provide baseline information in the understanding of the legume rhizobium symbiosis for the selection and development of effective nodulation and nitrogen fixing strains for forage and pasture improvement.
Ameen Al-Ali
Research Institute Charles Viollette, France
Title: Behavior of plant growth promoting bacteria in tomato rhizosphere:Colonization of rhizosphere as influenced by PGPR and root exudates composition
Biography:
Dr. Ameen Al-Ali ks currently working in Research Institute Charles Viollette, France
Abstract:
Plant growth promoting bacteria (PGPR) are an indispensable part of rhizosphere biota that when grown in association with the host plants can stimulate the growth of the host. PGPR promote plant growth directly by either facilitating resource acquisition (nitrogen, phosphorus and essential minerals) or modulating plant hormone levels, or indirectly by decreasing the inhibitory effects of various pathogens on plant growth and development in the forms of biocontrol agents. Different strains of B.subtilis and B.amyloliquefaciens among PGPR produce different non-ribosomal peptides such as cyclic lipopeptides. Surfactin, Fengycin and Iturin are cyclic lipopeptides produce by B.subtilis, and B. amyloliquefaciens, they play an important role in the rhizosphere to suppress the plant pathogens and thus, it improves the relationship between PGPR and host plant. The colonization is the most important criterion to PGPR and it influences by different factors: plants species, PGPR and their lipopeptides production, rhizosphere conditions, and root exudates and their compositions. At this work, we highlighted to study the effect of root exudates, and some of their compositions on the rhizosphere colonization, in addition, to study the surfactin role on this criterion. Two strains, B.subtilis BBG131, and B.amyloliquefaciens FZB42 were chosen to evaluate their behavior in the rhizosphere and their growth in the root exudates and some of carbon sources found in root exudates. B.subtilis BBG131 produces only surfactin and B.amyloliquefaciens produces three lipopeptides families: Iturin, Fengycin, and Surfactin. The results showed a significant different in bacterial growth between B.amyloliquefaciens and B.subtilis. Glucose, sucrose and maltose were the best carbon sources for B.amyloliquefaciens FZB42. In all carbon sources the final biomass of B.subtilis BBG131 was less than with B.amyloliquefaciens FZB42. There was no growth of B.subtilis BBG131 with fumaric acid. Root exudates showed the ability to induce bacterial growth for two strains studied. B.amyloliquefaciens FZB42 indicated a high ability to colonize the tomato rhizosphere while the surfactin production was low. A contrary results present by B.subtilis BBG131, the rhizosphere colonization was very low, while the surfactin production was a high.
Hubert Antolak
Lodz University of Technology, Poland
Title: The varied adhesive abilities of acetic acid bacteria isolated from environmental and industrial sources.
Biography:
Hubert Antolak, finished his studies at the Lodz University of Technology, Faculty of Biotechnology and Food Science with engineer degree in Biotechnology in 2012. In 2013 receive master degree in Biotechnology at Biotechnology and Food Sciences Department. In the same year, at the Lodz University of Technology, began PhD studies at the Institute of Fermentation Technology and Microbiology, Department of Biotechnology and Food Sciences, Lodz University of Technology. He is co-autor of articles in Polish journals: Food. Science. Technology. Quality; Food Industry; Laboratory; Agro Industry; and article in BioMed Research International. He is co-author of nucleotide sequences deposited in GenBank database.
Abstract:
Acetic acid bacteria (AAB) are the members of Acetobacteraceae family, widespread in nature. The bacteria colonize the environments rich in saccharides occuring as a native microflora of flowers, fruits, honey. In biotechnology, AAB are vere important group of microorganisms used in vinegar biosynthesis, biocellulose production, biocatalysis. In other hand, the bacteria are responsible for contamination of alcoholic and nonalcoholic beverages coasing sensory-organoleptic changes of the product. A significant amount of products are contaminated by bacteria inhabit in a biofilm formed on the inner parts of the production line. Due to the high resistance of formed microbial structure and low efficiency of washing and disinfecting processes, the problem affects a growing number of companies. The objective of this study was to investigate adhesive abilities of acetic acid bacteria to packaging materials used in the food industry, both glass and PET (Ethylene Terephthalate). The experiments were performed with a 15 strains isolated from polish and exotic fruits and contaminated products. The analysis of adhesion to the carriers was performed by luminometry, the plate count method and microscopic observations. Biofouling during incubation had a dynamic and changeable character. The number of attached cells was significantly higher with PET surface. The highest values of RLU were obtained for Asaia lannensis strains isolated from the mineral flavoured water and grapes. Results of our study show that the less hydrophobic materials such as glass are much better for food industry. The microbial adhesion to this kind of material is less efficient with decreased probability of biofilm occurrence in production processes. " Acknowledgments-The research was financed by a grant from NCBiR implemented within the framework of the Programme of Applied Research - PBS1/B8/3/2012."
Monika Bright
University of Vienna, Austria
Title: Testing evolutionary theory in thiotrophic mutualism
Biography:
Monika Bright obtained her PhD at the University of Vienna in 1992, at the age of 29. She did her postdoctoral studies at the University of Tübingen, the Rosenstiel School of Marine and Atmospheric Science, and the Pennsylvania State University. Presently, she is University Professor for Zoology and Marine Biology and Vice Head of the Department of Limnology and Oceanography at the University of Vienna. She has published more than 70 papers in reputed journals and has been serving as editorial board member for Frontiers in Microbial Symbiosis and as councilor of the International Society of Symbiosis.
Abstract:
Evolutionary theory depicts inter-species cooperation as mutual beneficial for both partners. However, empirical efforts to investigate underlying, stabilizing mechanisms require systems, which can be experimentally manipulated or cultivated. One of the most diverse microbial mutualisms involves sulfur oxidizing, chemoautotrophic bacteria and protist or animal hosts known from diverse marine ecosystems. The system we study is the tubeworm Riftia pachyptila and its endosymbiont Cand. Endoriftia persephone from deep-sea hydrothermal vents. We also focus on the ciliate Zoothamnium niveum and its ectosymbiont Cand. Thiobios zoothamnicoli from shallow-water wood falls, which we managed to cultivate. Transmission, considered to play a key role in the evolution, is horizontal in Riftia and resembles pathogen infections. Here we show an active escape of Endoriftia upon host death and seeding of the environment. This crucial process enables the host to find the cooperating symbiont over generations thus facilitating persistence. New findings point to a mixed transmission mode in Zoothamnium. In contrast to Endoriftia, Thiobios escapes dead hosts as well as living hosts when sulfide flux ceases. Cultivation experiments point to partner fidelity feedback mechanisms over a wide range of environmental conditions, but also show under which circumstances the ciliate mutualism terminates rendering an aposymbiotic host with reduced fitness. This loner strategy is not possible for the gutless tubeworm entirely nourished by its symbiont. Such studies outline the importance of bridging the gap between theory and empirical tests in various beneficial microbial associations to better understand cooperation.
Semiu Kareem
Modibbo University of Technology, Nigeria
Title: A BENEFICIAL MICROBE, Desulfobacterium anilini
Biography:
Dr. Kareem S A is currently working in the Modibbo University of Technology, Nigeria
Abstract:
About 90% of the hydrocarbons mined from the Earth are burnt for energy. Their combustion produces oxides of sulfur and nitrogen which are the principal source of acid rain. Most countries have imposed regulations to control their release. At the refineries, hydrodesulfurization (HDS) is currently performed to remove sulfur compounds from fossil fuels. This process is done at high temperatures and pressures by metal catalysis and is effective for removing inorganic sulfur and simple organic sulfur compounds. However, it is difficult to remove heterocyclic sulfur compounds. The high cost and inherent chemical limitations associated with HDS make alternatives to this technology of interest to the petroleum industry. Biodesulfurization which has two pathways, namely the sulfur-specific oxidative and the sulfur-specific reductive pathways has attracted attention as an alternative process to HDS, The sulfur-specific oxidative pathway has been extensively studied, There are very few reports on the desulfurization activity of sulfur reducing bacteria on DBT under well controlled sulfur-reducing anaerobic conditions. Desulfobacterium anilini was isolated by enrichment in an anaerobic jar and was subsequently identified after series of characteristic biochemical and morphological tests. Thereafter, its suitability for anaerobic desulfurization was investigated, it was found that it has great capability for that purpose, it remove over 80% of heterocyclic sulfur in both kerosene and diesel. The kinetics of the heterocyclic sulfur compounds in kerosene follows the zero order while the Michaelis Menten model described the kinetics observed in the removal of heterocyclic sulfur compounds in diesel. In view of the aforementioned, it is logical to conclude that Desulfobacterium anilini has a great benefit in the industry as a biocatalyst for heterocyclic sulfur compounds removal in real petroleum products.