Time filter

Source Type

Lat Bua Luang, Thailand

Roongsawang N.,Bioresources Technology Unit | Washio K.,Hokkaido University | Morikawa M.,Hokkaido University
International Journal of Molecular Sciences | Year: 2011

Lipopeptide biosurfactants (LPBSs) consist of a hydrophobic fatty acid portion linked to a hydrophilic peptide chain in the molecule. With their complex and diverse structures, LPBSs exhibit various biological activities including surface activity as well as anti-cellular and anti-enzymatic activities. LPBSs are also involved in multi-cellular behaviors such as swarming motility and biofilm formation. Among the bacterial genera, Bacillus (Gram-positive) and Pseudomonas (Gram-negative) have received the most attention because they produce a wide range of effective LPBSs that are potentially useful for agricultural, chemical, food, and pharmaceutical industries. The biosynthetic mechanisms and gene regulation systems of LPBSs have been extensively analyzed over the last decade. LPBSs are generally synthesized in a ribosome-independent manner with megaenzymes called nonribosomal peptide synthetases (NRPSs). Production of active-form NRPSs requires not only transcriptional induction and translation but also post-translational modification and assemblage. The accumulated knowledge reveals the versatility and evolutionary lineage of the NRPSs system. This review provides an overview of the structural and functional diversity of LPBSs and their different biosynthetic mechanisms in Bacillus and Pseudomonas, including both typical and unique systems. Finally, successful genetic engineering of NRPSs for creating novel lipopeptides is also discussed. © 2010 by the authors; licensee MDPI, Basel, Switzerland.

Wongwilaiwalin S.,Bioresources Technology Unit | Laothanachareon T.,Bioresources Technology Unit | Mhuantong W.,Bioresources Technology Unit | Tangphatsornruang S.,Genome Institute | And 3 more authors.
Applied Microbiology and Biotechnology | Year: 2013

Decomposition of lignocelluloses by cooperative microbial actions is an essential process of carbon cycling in nature and provides a basis for biomass conversion to fuels and chemicals in biorefineries. In this study, structurally stable symbiotic aero-tolerant lignocellulose-degrading microbial consortia were obtained from biodiversified microflora present in industrial sugarcane bagasse pile (BGC-1), cow rumen fluid (CRC-1), and pulp mill activated sludge (ASC-1) by successive subcultivation on rice straw under facultative anoxic conditions. Tagged 16S rRNA gene pyrosequencing revealed that all isolated consortia originated from highly diverse environmental microflora shared similar composite phylum profiles comprising mainly Firmicutes, reflecting convergent adaptation of microcosm structures, however, with substantial differences at refined genus level. BGC-1 comprising cellulolytic Clostridium and Acetanaerobacterium in stable coexistence with ligninolytic Ureibacillus showed the highest capability on degradation of agricultural residues and industrial pulp waste with CMCase, xylanase, and β-glucanase activities in the supernatant. Shotgun pyrosequencing of the BGC-1 metagenome indicated a markedly high relative abundance of genes encoding for glycosyl hydrolases, particularly for lignocellulytic enzymes in 26 families. The enzyme system comprised a unique composition of main-chain degrading and side-chain processing hydrolases, dominated by GH2, 3, 5, 9, 10, and 43, reflecting adaptation of enzyme profiles to the specific substrate. Gene mapping showed metabolic potential of BGC-1 for conversion of biomass sugars to various fermentation products of industrial importance. The symbiotic consortium is a promising simplified model for study of multispecies mechanisms on consolidated bioprocessing and a platform for discovering efficient synergistic enzyme systems for biotechnological application. © 2013 Springer-Verlag Berlin Heidelberg.

Mhuantong W.,Bioresources Technology Unit | Charoensawan V.,Mahidol University | Kanokratana P.,Bioresources Technology Unit | Tangphatsornruang S.,Genome Institute | Champreda V.,Bioresources Technology Unit
Biotechnology for Biofuels | Year: 2015

Background: As one of the most abundant agricultural wastes, sugarcane bagasse is largely under-exploited, but it possesses a great potential for the biofuel, fermentation, and cellulosic biorefinery industries. It also provides a unique ecological niche, as the microbes in this lignocellulose-rich environment thrive in relatively high temperatures (50°C) with varying microenvironments of aerobic surface to anoxic interior. The microbial community in bagasse thus presents a good resource for the discovery and characterization of new biomass-degrading enzymes; however, it remains largely unexplored. Results: We have constructed a fosmid library of sugarcane bagasse and obtained the largest bagasse metagenome to date. A taxonomic classification of the bagasse metagenome reviews the predominance of Proteobacteria, which are also found in high abundance in other aerobic environments. Based on the functional characterization of biomassdegrading enzymes, we have demonstrated that the bagasse microbial community benefits from a large repertoire of lignocellulolytic enzymes, which allows them to digest different components of lignocelluoses into single molecule sugars. Comparative genomic analyses with other lignocellulolytic and non-lignocellulolytic metagenomes show that microbial communities are taxonomically separable by their aerobic "open" or anoxic "closed" environments. Importantly, a functional analysis of lignocellulose-active genes (based on the CAZy classifications) reveals core enzymes highly conserved within the lignocellulolytic group, regardless of their taxonomic compositions. Cellulases, in particular, are markedly more pronounced compared to the non-lignocellulolytic group. In addition to the core enzymes, the bagasse fosmid library also contains some uniquely enriched glycoside hydrolases, as well as a large repertoire of the newly defined auxiliary activity proteins. Conclusions: Our study demonstrates a conservation and diversification of carbohydrate-active genes among diverse microbial species in different biomass-degrading niches, and signifies the importance of taking a global approach to functionally investigate a microbial community as a whole, as compared to focusing on individual organisms. © 2015 Mhuantong et al.; licensee BioMed Central.

Wongwilaiwalin S.,Bioresources Technology Unit | Rattanachomsri U.,Bioresources Technology Unit | Laothanachareon T.,Bioresources Technology Unit | Eurwilaichitr L.,Bioresources Technology Unit | And 2 more authors.
Enzyme and Microbial Technology | Year: 2010

Degradation of lignocellulosic agro-industrial residues by means of complex microbial community is a promising approach providing efficient biomass decomposition for subsequent conversion to value-added products. In this study, an active thermophilic lignocellulose degrading microbial consortium was bred from high-temperature sugarcane bagasse compost by successive subcultivation under aerobic static conditions. The microbial consortium showed efficient degradation activity on potential biorefinery cellulosic substrates, including bagasse, rice straw, corn stover and industrial eucalyptus pulp sludge. The consortium was structurally stable with the co-existence of eight major microbes, comprising anaerobic bacterial genera Clostridium and Thermoanaerobacterium along with an aerobic/facultative anaerobic Rhodocyclaceae bacterium, bacilli, and uncultured bacteria. Majority of the lignocellullolytic activities including endo-glucanase, xylanase and β-glucanase was present in the crude culture supernatant compared to the cell-bound fraction. Proteomic analysis of cellulose bound fraction of the crude extracellular enzyme revealed a multi-species lignocellulolytic enzyme system composed mainly of cellulosomal components and extracellular cellulases of clostridia along with hemicellulases and a β-glucanase from Clostridium, Bacillus, and Thermobacillus related origins. This work presents the first report on analysis of the complex structurally stable lignocellulose degrading microbial consortium together with the characterization of its lignocellulolytic enzyme system applicable for biomass degradation and conversion in biotechnological industry. © 2010 Elsevier Inc.

Ingsriswang S.,Bioresources Technology Unit | Yokwai S.,Bioresources Technology Unit | Wichadakul D.,Bioresources Technology Unit
Bioinformatics | Year: 2011

Summary: LinkinPath is a pathway mapping and analysis tool that enables users to explore and visualize the list of gene/protein sequences through various Flash-driven interactive web interfaces including KEGG pathway maps, functional composition maps (TreeMaps), molecular interaction/reaction networks and pathway-to-pathway networks. Users can submit single or multiple datasets of gene/protein sequences to LinkinPath to (i) determine the co-occurrence and co-absence of genes/proteins on animated KEGG pathway maps; (ii) compare functional compositions within and among the datasets using TreeMaps; (iii) analyze the statistically enriched pathways across the datasets; (iv) build the pathway-to-pathway networks for each dataset; (v) explore potential interaction/reaction paths between pathways; and (vi) identify common pathway-to-pathway networks across the datasets. © The Author(s) 2011. Published by Oxford University Press.

Discover hidden collaborations