Abstract: Lignocellulosic carbohydrates, i.e. cellulose and hemicellulose, have abundant potential as feedstock for production of biofuels and chemicals. However, these carbohydrates are generally infiltrated by lignin. Breakdown of the lignin barrier will alter lignocelluloses structures and make the carbohydrates accessible for more efficient bioconversion. White-rot fungi produce ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) and efficiently mineralise lignin into CO2 and H2O. Biological pretreatment of lignocelluloses using white-rot fungi has been used for decades for ruminant feed, enzymatic hydrolysis, and biopulping. Application of white-rot fungi capabilities can offer environmentally friendly processes for utilising lignocelluloses over physical or chemical pretreatment. This paper reviews white-rot fungi, ligninolytic enzymes, the effect of biological pretreatment on biomass characteristics, and factors affecting biological pretreatment. Application of biological pretreatment for enzymatic hydrolysis, biofuels (bioethanol, biogas and pyrolysis), biopulping, biobleaching, animal feed, and enzymes production are also discussed.

Abstract: The ever increasing concerns over fluctuating price of oil and the possible future supply constrains have reinforced the need for alternative fuel resources. Use of synthesis gas (syngas) to generate fuels through a microbial route would likely be an option to address part of this challenge. Syngas fermentation offers a pathway for sustainable synthesis of fuels and chemicals with lots of advantages over catalytic syngas conversion. This work reviews the available literature on production of second generation biofuels from syngas using various biocatalysts. The potential of syngas fermentation using acetogenic, hydrogenogenic and methanogenic organisms have been surveyed. A vast variety of biofuels and biochemicals including ethanol, acetate, hydrogen, butanol, butyrate, methane and etc. have been produced from gaseous substrates using microbial catalysts. The role of various parameters including medium composition, fermentation pH, trace elements, reducing agents and mass transfer limitations on bioconversion process has been extensively discussed. From this survey of literature it has been deduced that despite years of research and endeavors, fermentation of syngas to biofuels is still a relatively immature technology and long-term view for this potential conversion should be undertaken for future commercial deployments.

Abstract: Hemicelluloses, the second most abundant polysaccharide in nature, are well suited for ethanol production due to their enormous availability, low cost and environmental benign process. The major fraction in hemeicelluloses is pentosans and the conversion of pentosans to ethanol is problematic. To get the process economized, the conversion of hemicellulose to ethanol with a satisfactory yield is necessary. In recent years, significant advances have been made towards the technology of pentosans to ethanol conversion. However, there are technical and economical impediments to the development of commercially viable processes utilizing hemicellulosic derived sugars. This article provides an overview of the new insights in pentose sugars conversion into ethanol, pentoses resources, microorganisms and the technology. Key words: Hemicellulose, bioethanol, pentose sugars, yeasts, fermentation.

Abstract: Biofuels produced from lignocellulosic biomass can significantly reduce the energy dependency on fossil fuels and the resulting effects on environment. In this respect, cellulosic ethanol as an alternative fuel has the potential to become a viable energy source in the near future. Over the past few decades, tremendous effort has been undertaken to make cellulosic ethanol cost competitive with conventional fossil fuels. The pretreatment step is always necessary to deconstruct the recalcitrant structures and to make cellulose more accessible to enzymes. A large number of pretreatment technologies involving physical, chemical, biological, and combined approaches have been developed and tested at the pilot scale. Furthermore, various strategies and methods, including multi-enzyme complex, non-catalytic additives, enzyme recycling, high solids operation, design of novel bioreactors, and strain improvement have also been implemented to improve the efficiency of subsequent enzymatic hydrolysis and fermentation. These technologies provide significant opportunities for lower total cost, thus making large-scale production of cellulosic ethanol possible. Meanwhile, many researchers have focused on the key factors that limit cellulose hydrolysis, and analyzing the reaction mechanisms of cellulase. This review describes the most recent advances on process intensification and mechanism research of pretreatment, enzymatic hydrolysis, and fermentation during the production of cellulosic ethanol.

Abstract: Propanediol (1,3-PD) is one of the important products used in chemical industry, in particular for polyesters production (e.g. polyethers and polyurethanes). Using crude glycerol for producing 1,3-PD is a good solution from the economical as well as ecological point of view. Glycerol produced by cleavage of natural fats can be microbially converted to 1.3-propanediol by, among others, Citrobacter, Klebsiella, Lactobacillus, Enterobacter, and Clostri- dium strains. Biotechnological production of 1,3-PD from waste biomass is a promising and attractive alternative to the traditional chemical synthesis. The production of 1,3-PD by glycerol fermentation was already reported in 1881. The microbiological bioconversion pathway of glycerol to 1,3-PD has been known for long but the micro- organisms taking part in this fermentation are not efficient. In addition, they are pathogenic. Consequently, na- tural producers of 1,3-PD are still being sought. In this review we present a historical outline of 1,3-PD produc- tion, as well as the microorganisms and their metabolic pathways that are involved in glycerol fermentation to 1,3-PD.

Abstract: Kawazoe, Y.; Shimogawa, H.; Sato, A.; Uesugi, M., Mitochondrial Surface-specific Fluorescent Probe Activated by Bioconversion, Angew. Chem. Int. Ed., 50(24), 5478-5481 (2011). Sumiya, E.; Shimogawa, H.; Sasaki, H.; Tsutsumi, M.; Yoshita, K.; Ojika, M.; Suenaga, K.; Uesugi, M., Cell-morphology Profiling of a Natural Product Library Identifies Bisebromoamide and Miuraenamide A as Actin-filament Stabilizers, ACS Chem. Biol., 6(5), 425-431 (2011). Shirakawa, T.; Kawazoe, Y.; Tsujikawa, T.; Jung, D.; Sato, S.; Uesugi, M., Deactivation of STAT6 through Serine 707 Phosphorylation by JNK, J. Biol. Chem., 286, 4003-4010 (2011). Sato, S; Murata, A.; Orihara, T.; Shirakawa, T.; Suenaga, K.; Kigoshi, H.; Uesugi, M., Marine Natural Product Aurilide Activates the OPA1mediated Apoptosis by Binding to Prohibitin, Chem. Biol., 18 (1), 131-139 (2011). Kamisuki, S.; Shirakawa, T.; Kugimiya, A.; Abu-Elheiga, L.; Choo, H. Y.; Yamada, K.; Shimogawa, H.; Wakil, S. J.; Uesugi, M., Synthesis and Evaluation of Diarylthiazole Derivatives that Inhibit Activation of Sterol Regulatory Element-binding Proteins, J. Med. Chem., 54(13), 4923-4927(2011). Murata, A.; Sato, S.; Kawazoe, Y.; Uesugi, M., Small-molecule Fuorescent Probes for Specific RNA Targets, Chem. Comm., 47, 4712-4714 (2011). Proj Res**** WATANABE, Mizuki (D Pharm Sc) Proj Res** JIN, Guihua (D Med Sc) Proj Res**,***** KUO, Ting-Fang (D Sc) Guest Scholar*** SHEN, Yan (D Med Sc)

Abstract: Softwoods are the dominant source of lignocellulosic biomass in the northern hemisphere, and have been investigated worldwide as a renewable substrate for cellulosic ethanol production. One challenge to using softwoods, which is particularly acute with pine, is that the pretreatment process produces inhibitory compounds detrimental to the growth and metabolic activity of fermenting organisms. To overcome the challenge of bioconversion in the presence of inhibitory compounds, especially at high solids loading, a strain of Saccharomyces cerevisiae was subjected to evolutionary engineering and adaptation for fermentation of pretreated pine wood (Pinus taeda). An industrial strain of Saccharomyces, XR122N, was evolved using pretreated pine; the resulting daughter strain, AJP50, produced ethanol much more rapidly than its parent in fermentations of pretreated pine. Adaptation, by preculturing of the industrial yeast XR122N and the evolved strains in 7% dry weight per volume (w/v) pretreated pine solids prior to inoculation into higher solids concentrations, improved fermentation performance of all strains compared with direct inoculation into high solids. Growth comparisons between XR122N and AJP50 in model hydrolysate media containing inhibitory compounds found in pretreated biomass showed that AJP50 exited lag phase faster under all conditions tested. This was due, in part, to the ability of AJP50 to rapidly convert furfural and hydroxymethylfurfural to their less toxic alcohol derivatives, and to recover from reactive oxygen species damage more quickly than XR122N. Under industrially relevant conditions of 17.5% w/v pretreated pine solids loading, additional evolutionary engineering was required to decrease the pronounced lag phase. Using a combination of adaptation by inoculation first into a solids loading of 7% w/v for 24 hours, followed by a 10% v/v inoculum (approximately equivalent to 1 g/L dry cell weight) into 17.5% w/v solids, the final strain (AJP50) produced ethanol at more than 80% of the maximum theoretical yield after 72 hours of fermentation, and reached more than 90% of the maximum theoretical yield after 120 hours of fermentation. Our results show that fermentation of pretreated pine containing liquid and solids, including any inhibitory compounds generated during pretreatment, is possible at higher solids loadings than those previously reported in the literature. Using our evolved strain, efficient fermentation with reduced inoculum sizes and shortened process times was possible, thereby improving the overall economic viability of a woody biomass-to-ethanol conversion process.

Abstract: Publisher Summary The syngas can be converted into liquid biofuels through Fischer-Tropsch (FT) synthesis (using metal catalysts) or direct microbial fermentation knownas syngas fermentation (using microbial catalysts). The FT synthesis usually utilizes metal catalysts such as cobalt (Co), ferrous (Fe), copper (Cu), aluminum (Al), zinc (Zn), molybdenum (Mo), nickel (Ni), rubidium (Ru), and ruthenium (Rh). The major drawbacks of FT synthesis are the high costs of the metal catalyst, a fixed H2:CO ratio (2:1), catalyst poisoning due to inert gases and contaminants containing sulfur, and high operating temperature and pressure. Syngas fermentation via biocatalysts (such as Clostridium ljungdahlii, C. autoethanogenum, C. carboxydivorans, Butyribacterium methylotrophicum, Methanosarcina barkeri, and Rhodospirillum rubrum) produces liquid/gaseous biofuels, and offers several advantages over the biochemical approach and the FT process. Some of the merits of syngas fermentation are the elimination of the need of expensive metal catalysts, a higher specificity of the biocatalysts, the independence of theH2:CO ratio for bioconversion, the operation of bioreactors at ambient conditions, and the elimination of issues concerning noble metal poisoning Biomass-derived syngas fermentation to biofuels is identified as a sustainable alternative for the fast depleting fossil-derived fuels. The process has several advantages including higher availability, low feedstock cost, and no competition with food and feed. The commercialization of syngas fermentation to biofuels is often plagued by the gas-to-liquid mass transfer limitations and low product yield. Innovative reactors designs and metabolic engineering aspects are being studied extensively in recent literature focusing on higher product yields. Use of CHFM (composite hollow fiber membrane) in syngas fermentation is at its infant stage and needs extensive research to prove its economic and scale-up feasibilities. Similarly, research efforts should also be directed toward production of other biofuel such as butanol and gaseous fuel, methane.

Abstract: The feruloyl esterase expressed in Depol 740L from Humicola spp. exhibited esterifying activity for the feruloylation of selected di- and oligosaccharides in a surfactant-less microemulsion medium composed of n-hexane, 2-butanone and MES–NaOH buffer (51:46:3, v/v/v). As compared to their corresponding ferulic acid, the feruloylated di- and oligosaccharides demonstrated similar or higher potential radical scavenging properties. By varying the media composition, the highest bioconversion yields were obtained in the n-hexane, 2-butanone and MES–NaOH buffer mixture using arabinobiose (8%), xylobiose (9%) and raffinose (11%) as substrates. However, using galactobiose as substrate, the highest bioconversion yield (27%) was obtained in the n-hexane, 1,4-dioxane and MES–NaOH buffer mixture. The chemical structure of the feruloylated di- and oligosaccharides was confirmed by APCI-MS. Response surface methodology, based on a 5-level and 4-factor central composite rotatable design revealed that enzyme amount and substrate molar ratio were the most important variables for the bioconversion yield of feruloylated raffinose.

Abstract: 1,3-Propanediol (PD) is an important chemical product which can be used for synthesis reactions, in particular, as a monomer for polycondensations to produce polyesters, polyethers and polyurethanes. It is produced by two methods, chemical synthesis and microbial conversion. Recently, the increasing interest in microbial conversion was observed. Glycerol is used as a substrate in this process and it may be fermented to 1,3-PD by, among others, Citrobacter ssp., Klebsiella ssp., Lactobacillus ssp., Enterobacter ssp. and Clostridium ssp. strains. The process of microbiological bioconversion pathway of glycerol to 1,3-PD is well known for a long time but microorganisms taking part in this fermentation are pathogenic. Thus, natural producers of 1,3-PD that are non-pathogenic and efficient enough, are still sought. This review deals with the case of 1,3-PD production and microbial formation of 1,3-PD, especially by Clostridium ssp. Moreover, it presents genetic engineering methods used in increasing microorganisms’ efficiency in the glycerol to 1,3 PD fermentation. Key words : 1,3-Propanediol, Clostridium ssp., fermentation, glycerol.

Abstract: The ultrasonic impact and possibilities of using its damaging effect on lignocellulosic material in order to increase the reactivity of plant biomass are studied. The main aim of pretreatment is the disruption of the crystalline, highly ordered structures of cellulose and lignin, or the removal of the latter. At the selected optimum parameters of ultrasonic pretreatment (frequency, 30 kHz) of the raw material, degradation of cellulose reaches 16% of a.d.s. (absolutely dry substance) while that of lignin is 11.4 % of a.d.s. Pretreatment of a substrate with ultrasound changes the rate and depth of the destruction of the initial material in the course of cultivation and can be used to accelerate the bioconversion of lignocellulosic substrates in biodiesel fuel production.

Abstract: A new versatile acrylonitrile-bioconverting strain isolated from a petroleum-contaminated sludge sample and identified as Rhodococcus ruber AKSH-84 was used for optimization of medium and biotransformation conditions for nitrilase activity to produce acrylic acid. A simple and rapid HPLC protocol was optimized for quantification of acrylic acid, acrylamide, and acrylonitrile. The optimal medium conditions for nitrilase activity were pH of 7.0, temperature of 30degreesC, agitation of 150 rpm, and inoculum level of 2%. Glycerol as a carbon source and sodium nitrate as the nitrogen source provided good nutritional sources for achieving good biotransformation. Nitrilase activity was constitutive in nature and was in the exponential growth phase after 24 h of incubation under optimal conditions without addition of any inducer. The substrate preference was acrylonitrile and acetonitrile. The present work demonstrates the biotransformation of acrylonitrile to acrylic acid with the new strain, R. ruber AKSH-84, which can be used in green biosynthesis of acrylic acid for biotechnological processes. The nitrilase produced by the isolate was purified and characterized.

Abstract: By year 2012, Mexico plans to substitute 880 million liters of gasoline oxygenate with ethanol. This represents the bioconversion of 2.2 or 16 million tons o...

Abstract: L-arabinose isomerases catalyse the isomerization of L-arabinose into L-ribulose at insight biological systems. At industrial scale of this enzyme is used for the bioconversion of D-galactose into D-tagatose which has many applications in pharmaceutical and agro-food industries. The isomerization reaction is thermodynamically equilibrated, and therefore the bioconversion rates is shifted towards tagatose when the temperature is increased. Moreover, to prevent secondary reactions it will be of interest to operate at low pH. The profitability of this D-tagatose production process is mainly related to the use of lactose as cheaper raw material. In many dairy products it will be interesting to produce D-tagatose during storage. This requires an efficient L-arabinose isomerase acting at low temperature and pH values. The gene encoding the L-arabinose isomerase from Shewanella sp. ANA-3 was cloned and overexpressed in Escherichia coli. The purified protein has a tetrameric arrangement composed by four identical 55 kDa subunits. The biochemical characterization of this enzyme showed that it was distinguishable by its maximal activity at low temperatures comprised between 15-35°C. Interestingly, this biocatalyst preserves more than 85% of its activity in a broad range of temperatures from 4.0 to 45°C. Shewanella sp. ANA-3 L-arabinose isomerase was also optimally active at pH 5.5-6.5 and maintained over 80% of its activity at large pH values from 4.0 to 8.5. Furthermore, this enzyme exhibited a weak requirement for metallic ions for its activity evaluated at 0.6 mM Mn2+. Stability studies showed that this protein is highly stable mainly at low temperature and pH values. Remarkably, T268K mutation clearly enhances the enzyme stability at low pH values. Use of this L-arabinose isomerase for D-tagatose production allows the achievement of attractive bioconversion rates of 16% at 4°C and 34% at 35°C. Here we reported the purification and the biochemical characterization of the novel Shewanella sp. ANA-3 L-arabinose isomerase. Determination of the biochemical properties demonstrated that this enzyme was highly active at low temperatures. The generated T268K mutant displays an increase of the enzyme stability essentially at low pH. These features seem to be very attractive for the bioconversion of D-galactose into D-tagatose at low temperature which is very interesting from industrial point of view.