Daily assessment of malting-induced changes in the volatile composition of barley (Hordeum vulgare L.), rye (Secale cereale L.), and quinoa (Chenopodium quinoa Willd.).

Barley (Hordeum vulgare L.) is the traditional malting cereal and is primarily used for beverages, whereas rye (Secale cereale L.) is mainly used in baked goods. Conversely, quinoa (Chenopodium quinoa Willd.) is a gluten-free pseudocereal, rich in starch and high-quality proteins, and can be used in a similar manner to cereals. The sharp bitterness of unprocessed rye and the earthy aroma of native quinoa interfere with the acceptance and development of food products. Malting of barley is known to improve its processing properties and enhance its sensory quality. Therefore, the effect of germination and kilning on malt quality (e.g., viscosity) as well as the volatile composition of barley, rye, and quinoa were monitored. Moreover, temporal changes on the volatile patterns of rye and quinoa at the different stages of malting were compared to barley. In total, 34 volatile compounds were quantified in the three (pseudo)cereals; the alcohol group dominated in all unprocessed samples, in particular, compounds contributing grassy notes (e.g., hexan-1-ol). These grassy compounds remained abundant during germination, whereas kilning promoted the formation of Maillard reaction volatiles associated with malty and roasted notes. The volatile profiles of kilned barley and quinoa were characterized by high concentrations of the malty Strecker aldehyde, 3-methylbutanal. In contrast, green, floral notes imparted by phenylacetaldehyde remained dominant in rye malt. Hierarchical cluster analysis of the volatile data discriminated the samples into the different stages of malting, confirmed the similarities in the volatile patterns of barley and rye, and indicated clear differences to the quinoa samples. PRACTICAL APPLICATION: In this study, the effect of germination and kilning on the chemical and volatile composition of barley, rye, and quinoa was examined. Temporal changes on the volatile patterns of rye and quinoa at different stages of malting were compared to barley. Understanding the differences among the (pseudo)cereals as well as the influence of processing on malt quality and aroma development can help find new food applications.

Techno-economic and Life Cycle Analysis of MixAlco® Processes for Mixed Alcohol Production from Brown Algae.

The need for producing renewable fuels from biomass has increased due to depleting fossil resources and environmental concerns. However, the low fraction of biomass carbon converted to product is an undeniable drawback for most current biofuel productions from fermentation due to undecomposed lignin in biomass composition and carbon loss as CO2. In this work, two main production routes of the MixAlco® process, the ketonization route (KR) and esterification route (ER) are evaluated for the mixed alcohol production by brown algae, a third-generation biomass without lignin. A novel fermentation process using syntrophic bacteria consortia (SBC) is developed to produce acetic acid from waste gas produced by KR and ER process. The paper investigates the integrated flowsheet for these alternative routes, using techno-economic and life cycle analysis to compare the minimum selling price and environmental impacts. From TEA, we find that the overall costs for KR and ER are lower than the SBC processes. The cost of ketonization routes is lower than esterification routes. The capital cost and operating cost for the ER+SBC process are the highest. Raw materials and utilities are the two major costs for all the processing routes examined. The MSP for the ER+SBC process is the lowest out of all four routes. ER process performs the best in terms of environmental impacts except in water depletion compared with other processes, while the KR process performs the worst regarding the environmental metrics.

In vitro assessment of 3-alkoxy-5-nitroindazole-derived ethylamines and related compounds as potential antileishmanial drugs.

Leishmaniasis is a widespread neglected tropical disease complex that is responsible of one million new cases per year. Current treatments are outdated and pose many problems that new drugs need to overcome. With the goal of developing new, safe, and affordable drugs, we have studied the in vitro activity of 12 different 5-nitroindazole derivatives that showed previous activity against different strains of Trypanosoma cruzi in a previous work. T. cruzi belongs to the same family as Leishmania spp., and treatments for the disease it produces also needs renewal. Among the derivatives tested, compounds 1, 2, 9, 10, 11, and 12 showed low J774.2 macrophage toxicity, while their effect against both intracellular and extracellular forms of the studied parasites was higher than the ones found for the reference drug Meglumine Antimoniate (Glucantime®). In addition, their Fe-SOD inhibitory effect, the infection rates, metabolite alteration, and mitochondrial membrane potential of the parasites treated with the selected drugs were studied in order to gain insights into the action mechanism, and the results of these tests were more promising than those found with glucantime, as the leishmanicidal effect of these new drug candidates was higher. The promising results are encouraging to test these derivatives in more complex studies, such as in vivo studies and other experiments that could find out the exact mechanism of action.

Highly engineered biocatalysts for efficient small molecule pharmaceutical synthesis.

Technologies for the engineering of biocatalysts for efficient synthesis of pharmaceutical targets have advanced dramatically over the last few years. Integration of computational methods for structural modeling, combined with high through put methods for expression and screening of biocatalysts and algorithms for mining experimental data, have allowed the creation of highly engineered biocatalysts for the efficient synthesis of pharmaceuticals. Methods for the synthesis of chiral alcohols and amines have been particularly successful, along with the creation of non-natural activities for such desirable reactions as cyclopropanation and esterification.

Assessment of hydrogen metabolism in commercial anaerobic digesters.

Degradation of biomass in the absence of exogenous electron acceptors via anaerobic digestion involves a syntrophic association of a plethora of anaerobic microorganisms. The commercial application of this process is the large-scale production of biogas from renewable feedstock as an alternative to fossil fuels. After hydrolysis of polymers, monomers are fermented to short-chain fatty acids and alcohols, which are further oxidized to acetate. Carbon dioxide, molecular hydrogen (H2), and acetate generated during the process are converted to methane by methanogenic archaea. Since many of the metabolic pathways as well as the syntrophic interactions and dependencies during anaerobic digestion involve formation, utilization, or transfer of H2, its metabolism and the methanogenic population were assessed in various samples from three commercial biogas plants. Addition of H2 significantly increased the rate of methane formation, which suggested that hydrogenotrophic methanogenesis is not a rate-limiting step during biogas formation. Methanoculleus and Methanosarcina appeared to numerically dominate the archaeal population of the three digesters, but their proportion and the Bacteria-to-Archaea ratio did not correlate with the methane productivity. Instead, hydrogenase activity in cell-free extracts from digester sludge correlated with methane productivity in a positive fashion. Since most microorganisms involved in biogas formation contain this activity, it approximates the overall anaerobic metabolic activity and may, thus, be suitable for monitoring biogas reactor performance.

Scale-up and intensification of (S)-1-(2-chlorophenyl)ethanol bioproduction: economic evaluation of whole cell-catalyzed reduction of o-chloroacetophenone.

Escherichia coli cells co-expressing genes coding for Candida tenuis xylose reductase and Candida boidinii formate dehydrogenase were used for the bioreduction of o-chloroacetophenone with in situ coenzyme recycling. The product, (S)-1-(2-chlorophenyl)ethanol, is a key chiral intermediate in the synthesis of polo-like kinase 1 inhibitors, a new class of chemotherapeutic drugs. Production of the alcohol in multi-gram scale requires intensification and scale-up of the biocatalyst production, biotransformation, and downstream processing. Cell cultivation in a 6.9-L bioreactor led to a more than tenfold increase in cell concentration compared to shaken flask cultivation. The resultant cells were used in conversions of 300 mM substrate to (S)-1-(2-chlorophenyl)ethanol (e.e. >99.9%) in high yield (96%). Results obtained in a reaction volume of 500 mL were identical to biotransformations carried out in 1 mL (analytical) and 15 mL (preparative) scale. Optimization of product isolation based on hexane extraction yielded 86% isolated product. Biotransformation and extraction were accomplished in a stirred tank reactor equipped with pH and temperature control. The developed process lowered production costs by 80% and enabled (S)-1-(2-chlorophenyl)ethanol production within previously defined economic boundaries. A simple and efficient way to synthesize (S)-1-(2-chlorophenyl)ethanol in an isolated amount of 20 g product per reaction batch was demonstrated.

Microbial engineering for the production of advanced biofuels.

Advanced biofuels produced by microorganisms have similar properties to petroleum-based fuels, and can 'drop in' to the existing transportation infrastructure. However, producing these biofuels in yields high enough to be useful requires the engineering of the microorganism's metabolism. Such engineering is not based on just one specific feedstock or host organism. Data-driven and synthetic-biology approaches can be used to optimize both the host and pathways to maximize fuel production. Despite some success, challenges still need to be met to move advanced biofuels towards commercialization, and to compete with more conventional fuels.

Integrative analysis of transgenic alfalfa (Medicago sativa L.) suggests new metabolic control mechanisms for monolignol biosynthesis.

The entanglement of lignin polymers with cellulose and hemicellulose in plant cell walls is a major biological barrier to the economically viable production of biofuels from woody biomass. Recent efforts of reducing this recalcitrance with transgenic techniques have been showing promise for ameliorating or even obviating the need for costly pretreatments that are otherwise required to remove lignin from cellulose and hemicelluloses. At the same time, genetic manipulations of lignin biosynthetic enzymes have sometimes yielded unforeseen consequences on lignin composition, thus raising the question of whether the current understanding of the pathway is indeed correct. To address this question systemically, we developed and applied a novel modeling approach that, instead of analyzing the pathway within a single target context, permits a comprehensive, simultaneous investigation of different datasets in wild type and transgenic plants. Specifically, the proposed approach combines static flux-based analysis with a Monte Carlo simulation in which very many randomly chosen sets of parameter values are evaluated against kinetic models of lignin biosynthesis in different stem internodes of wild type and lignin-modified alfalfa plants. In addition to four new postulates that address the reversibility of some key reactions, the modeling effort led to two novel postulates regarding the control of the lignin biosynthetic pathway. The first posits functionally independent pathways toward the synthesis of different lignin monomers, while the second postulate proposes a novel feedforward regulatory mechanism. Subsequent laboratory experiments have identified the signaling molecule salicylic acid as a potential mediator of the postulated control mechanism. Overall, the results demonstrate that mathematical modeling can be a valuable complement to conventional transgenic approaches and that it can provide biological insights that are otherwise difficult to obtain.

Gas chromatographic assessment of alcoholyzed fatty acids from yeasts: a new chemotaxonomic method.

An alternative chemotaxonomic method to methanolysis was developed for gas chromatographic assessment of fatty acids in whole yeast cells. Clinical and reference strains of the medically important yeasts Candida albicans, Torulopsis glabrata, and Saccharomyces cerevisiae were cultured for 48 h at 26 degrees C. Cellular lysis and transesterification were then performed with ethanol, propanol, butanol, or methanol. The relative recovery rates for cellular fatty acids, including the volatile acids C10:0 and C12:0, were similar after alcoholysis with ethanol, propanol, or butanol, while methanolysis gave lower recoveries of volatile fatty acids. Thus, after ethanolysis, the recovery of C10:0 acid (0.1, 1, and 10%) from a defined matrix (lyophilized Actinobacillus actinomycetemcomitans cells) varied from 97 to 102%, while the recovery of C10:0 after methanolysis varied from 49 to 75%. This indicated that with the frequently used methanolysis technique, there is a considerable loss of volatile fatty acids. These acids may be used as marker molecules for taxonomic differentiation between yeasts.