Production Of Aromatic Compounds Research Articles

Producing monoaromatic compounds from pyrolytic vapour of rice straw using H-ZSM-5/B2O3 catalyst

The catalytic conversion of rice straw was done to produce mono aromatic compounds. The mixed catalyst of ZSM-5 and B2O3 was obtained through calcination of ZSM-5 and H3BO catalyst mixture. The variation of the composition of the ZSM-5 and B2O3 catalyst was applied in order to test the effect of catalyst composition to the production of mono aromatics compounds. The composition of catalyst used were 15% ZSM-5, 30% ZSM-5, and 100% ZSM-5. Other than the variation of catalyst composition, the variation of the operating temperature of the catalytic conversion also performed in order to study the effect of the temperature to the production of mono aromatic compounds. The catalytic conversion was done at 450, 475, and 500 oC. Experimental results show that the addition of the catalyst resulted in the conversion of oxygenate compounds resulted from the pyrolytic process of rice straw into mono aromatic compounds. It also shows that using 100% ZSM-5 produced the highest yield of mono aromatics compounds. The amount of mono aromatic compounds produced will decrease, as the fraction of ZSM-5 catalyst used and operation temperature also decreased. Using the 100% ZSM-5, the mono aromatics compound with the highest yield is 1, 3 Dimethyl benzene or mxylene.

Rational design and medium optimization for shikimate production in recombinant Bacillus licheniformis strains

Shikimate is a key intermediate for the synthesis of an anti-influenza drug sold under the trade name Tamiflu®. The metabolic pathway of shikimate has been extensively explored in Escherichia coli. This paper presents a rational strategy via cumulative disruption and overexpression of rate-limiting genes in Bacillus licheniformis, which is a GRAS (Generally Recognized as Safe) strain with high potential for the production of shikimate. The enhanced production of shikimate was achieved by the deletion of shikimate kinase (AroK) and pyruvate kinase (Pyk) as well as overexpression of transketolase (Tkt), 3-deoxy-d-arabinoheptulosonate-7-phosphate (DAHP) synthase (AroA), and shikimate dehydrogenase (AroD) respectively and the amount of byproducts was reduced significantly. Furthermore, the medium was optimized by an orthogonal test, and the titer of shikimate (21.8 g/L) produced by the strain WX-02ΔaroKΔpyk/pHY300-aroD increased by 56.8% compared to the original medium. This work revealed a new GRAS platform for the production of shikimate. These findings also suggest that B. licheniformis has great potential for the production of aromatic compounds of the extended shikimate pathway.

Physiological, phytochemicals and molecular analysis of color and scent of different landraces of Rosa damascena during flower development stages

Abstract Rosa damascena is one of important flowers for the production of aromatic compounds mainly used in perfume industry. In this research, complete sequences of gene coding geranylgeranyl diphosphate synthesis (GGPPS) involved in monoterpenes biosynthesis pathway was isolated from Rosa damascena “Kamoorˮ, and the relative expression of genes GGPPS, DXR, and CCD1 was characterized during flower developmental stages (A, B and C) in petals of four landraces of damask roses (Ghalhar, Lavasanat, Kamoor and Minab) by real-time quantitative fluorescence PCR. The overall expression of GGPPS gene was lower as compared with those of gene CCD1 and DXR. To further study, comprehensive analysis were done among physiological, molecular and phytochemical results to evaluate the relationship between main volatile compounds and colors. The output data revealed that damask roses with light colored flowers showed carotenoid accumulation and accommodation of higher carotenoid content and low anthocyanin content. Main volatile including citronellol, geraniol, neral, lianlyl acetate and dihydro citronellol acetate in flower development increase in the early stage, peaking in stage B and decreasing thereafter. These results suggest that the gene GGPPS may play role in the biosynthesis of volatile monoterpenes in R. damascena flowers, and this gene could be an important candidate genes for the regulation of secondary metabolism for Damask rose aromatic components.

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains.

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

Production of Bioactive Peptides in Tomato Seed Protein Isolate Fermented by Water Kefir Culture: Optimization of the Fermentation Conditions

The aim of this work was to explore the use of protein isolate from tomato seed as a medium for the growth of water kefir mixture culture. Response surface methodology (RSM) and a central composite rotatable design were used to optimize the fermentation conditions of tomato seed isolate by water kefir mixture culture, including inoculum level, sucrose concentration and ascorbic acid concentrations, in order to improve cell growth and exopolysaccharides production. The models established showed that the values of R2 were high and the p-values < 0.0001 were also suitable for this experiment, which confirmed the effectiveness of these models. The evaluation of the radical scavenging activity of the isolate after 24 h of fermentation showed an improvement of about 74%. HPLC analysis showed a significant decrease of the concentration of total amino-acids exceeding 155%, especially for glutamic acid and aspartic acid. After 24 h of fermentation, the protein isolate contains respectively by about 41.27 and 20.29 mg/100 g of glutamic acid and aspartic acid. FTIR results showed that the fermentation favors the production of new amides and aromatic compounds. The results of these experiments indicated that RSM design is promising approach for the optimization of tomato isolate fermentation conditions, and that water kefir culture could degrade and convert the proteins into bioactive peptides that contribute positively in the improvement of antioxidant activity.

Production and Characterization of a Distilled Alcoholic Beverage Obtained by Fermentation of Banana Waste (Musa cavendishii) from Selected Yeast

Banana is one of the most important fruits in the Brazilian diet and is mainly consumed naturally. Losses from crop to final consumer are high and estimated in about 30%. The aim of this work was to elaborate a distilled alcoholic beverage from discarded banana and to compare with commercial trademarks. Initially, yeast strains were isolated from banana fruit and characterized by their production of volatile aroma compounds. The highest aroma-producing yeast isolate was identified by ITS-rRNA gene sequencing as Pichia kluyveri. Pasteurized banana pulp and peel was fermented by the selected P. kluyveri at approximately 107 cells/mL. The sugars were converted quickly, and a high ethanol concentration (413 mg/L) was achieved after 24 h of fermentation. The fermented banana must was distilled in a Femel Alambic, and the head, heart and tail fractions were collected. The banana brandy produced had highest concentration of volatile compounds compared to trademarks, such as isoamyl acetate (13.5 mg/L), ethyl hexanoate (0.8 mg/L) and others. The results showed that whole banana must could be a good substrate for fermentation and distillation, and the sensory analysis performed revealed that the produced beverage had good acceptance by the tasters. This study demonstrates the potential of banana as a possible alternative to reduce waste and increase income to farmers.

Electrochemical Lignin Degradation in Ionic Liquids on Ternary Mixed Metal Electrodes

Abstract Lignin is the second most abundant natural polymer and a promissing feedstock for the generation of renewable aromatic chemicals. We present an fundamental approach for the electrocatalytic cleavage of lignin dissolved in a recoverable, inexpensive ionic liquid using mixed metal oxide electrodes of different compositions. The distribution of depolymerization products generated by electrochemical oxidation were analyzed by means of mass spectrometry. The distribution and yield of the cracked species was found to depended strongly on the implemented metal catalyst and therefore offers the potential to tailor the amount and composition of the low molecular weight cleavage products. This approach could help to provide a more sustainable valorization of lignin for the potential production of high value aromatic compounds due to synergistic effects.

New Lager Brewery Strains Obtained by Crossing Techniques Using Cachaça (Brazilian Spirit) Yeasts.

The development of hybrids has been an effective approach to generate novel yeast strains with optimal technological profile for use in beer production. This study describes the generation of a new yeast strain for lager beer production by direct mating between two Saccharomyces cerevisiae strains isolated from cachaça distilleries: one that was strongly flocculent, and the other with higher production of acetate esters. The first step in this procedure was to analyze the sporulation ability and reproductive cycle of strains belonging to a specific collection of yeasts isolated from cachaça fermentation vats. Most strains showed high rates of sporulation, spore viability, and homothallic behavior. In order to obtain new yeast strains with desirable properties useful for lager beer production, we compare haploid-to-haploid and diploid-to-diploid mating procedures. Moreover, an assessment of parental phenotype traits showed that the segregant diploid C2-1d generated from a diploid-to-diploid mating experiment showed good fermentation performance at low temperature, high flocculation capacity, and desirable production of acetate esters that was significantly better than that of one type lager strain. Therefore, strain C2-1d might be an important candidate for the production of lager beer, with distinct fruit traces and originating using a non-genetically modified organism (GMO) approach.IMPORTANCE Recent work has suggested the utilization of hybridization techniques for the generation of novel non-genetically modified brewing yeast strains with combined properties not commonly found in a unique yeast strain. We have observed remarkable traits, especially low temperature tolerance, maltotriose utilization, flocculation ability, and production of volatile aroma compounds, among a collection of Saccharomyces cerevisiae strains isolated from cachaça distilleries, which allow their utilization in the production of beer. The significance of our research is in the use of breeding/hybridization techniques to generate yeast strains that would be appropriate for producing new lager beers by exploring the capacity of cachaça yeast strains to flocculate and to ferment maltose at low temperature, with the concomitant production of flavoring compounds.

Glycolytic Functions Are Conserved in the Genome of the Wine Yeast Hanseniaspora uvarum, and Pyruvate Kinase Limits Its Capacity for Alcoholic Fermentation.

Hanseniaspora uvarum (anamorph Kloeckera apiculata) is a predominant yeast on wine grapes and other fruits and has a strong influence on wine quality, even when Saccharomyces cerevisiae starter cultures are employed. In this work, we sequenced and annotated approximately 93% of the H. uvarum genome. Southern and synteny analyses were employed to construct a map of the seven chromosomes present in a type strain. Comparative determinations of specific enzyme activities within the fermentative pathway in H. uvarum and S. cerevisiae indicated that the reduced capacity of the former yeast for ethanol production is caused primarily by an ∼10-fold-lower activity of the key glycolytic enzyme pyruvate kinase. The heterologous expression of the encoding gene, H. uvarumPYK1 (HuPYK1), and two genes encoding the phosphofructokinase subunits, HuPFK1 and HuPFK2, in the respective deletion mutants of S. cerevisiae confirmed their functional homology.IMPORTANCEHanseniaspora uvarum is a predominant yeast species on grapes and other fruits. It contributes significantly to the production of desired as well as unfavorable aroma compounds and thus determines the quality of the final product, especially wine. Despite this obvious importance, knowledge on its genetics is scarce. As a basis for targeted metabolic modifications, here we provide the results of a genomic sequencing approach, including the annotation of 3,010 protein-encoding genes, e.g., those encoding the entire sugar fermentation pathway, key components of stress response signaling pathways, and enzymes catalyzing the production of aroma compounds. Comparative analyses suggest that the low fermentative capacity of H. uvarum compared to that of Saccharomyces cerevisiae can be attributed to low pyruvate kinase activity. The data reported here are expected to aid in establishing H. uvarum as a non-Saccharomyces yeast in starter cultures for wine and cider fermentations.

Indigenous yeasts perform alcoholic fermentation and produce aroma compounds in wine

The spontaneous alcoholic fermentations of Moscato Bianco and Welschriesling must were carried out to retrieve indigenous yeasts. We confirmed that those fermentations, conducted with non-Saccharomyces and indigenous Saccharomyces cerevisiae yeasts, can generate high amounts of aroma compounds in wines. Consequently, two of the S. cerevisiae isolates were randomly chosen and further examined in Welschriesling and Sauvignon Blanc must for their ability and efficiency in performing alcoholic fermentation. Alcoholic fermentation with a commercial yeast strain was carried out for comparison. Indigenous isolates showed acceptable fermentation ability and efficiency. Moreover, Sauvignon Blanc produced with indigenous isolates contained significantly higher amounts of 3-mercaptohexyl acetate, linalool, geraniol and 2-phenylethanol and a significantly lower amount of 3-mercaptohexan-1-ol. Differences in Welschriesling wine were less striking but in this case indigenous isolates produced lower amounts of 3-mercaptohexan-1-ol and α-terpineol. Taken together, our results confirm that a suitable aromatic profile of wine can be produced with indigenous S. cerevisiae strains.

Effect of bed material, lignin content, and origin on the processability of biomass in fast pyrolysis reactors

AbstractLignin has great potential for the production of valuable aromatic compounds and has attracted considerable attention. The development of high value applications for Kraft lignin would boost the profitability of pulp and paper operations. A potential solution is the pyrolytic conversion of lignin to valuable liquids and solids. However, Kraft lignin is a thermally sensitive powder which tends to agglomerate under pyrolysis conditions. A mechanically fluidized reactor (MFR) can be used to monitor both the generation of vapours and gas during pyrolysis and how cohesive a feedstock becomes when pyrolyzed. The MFR was, therefore, used to evaluate alternative solutions to improve Kraft lignin behaviour by mixing it with non‐problematic feedstocks or by modifying its bed material. Finally, Kraft lignin behaviour and products were compared to those of hydrolysis lignins from different origins.

Establishing an Artificial Pathway for De Novo Biosynthesis of Vanillyl Alcohol in Escherichia coli

Vanillyl alcohol is a phenolic alcohol and is used as a flavoring agent in foods and beverages. In this paper, we propose a novel artificial pathway for microbial production of vanillyl alcohol from simple carbon sources. The pathway extends from 4-hydroxybenzoic acid (4-HBA), and needs only three heterologous enzymes, p-hydroxybenzoate hydroxylase (PobA), carboxylic acid reductase (CAR) and caffeate O-methyltransferase (COMT). First, we examined the promiscuous activity of COMT toward 3,4-dihydroxybenzyl alcohol and found a kcat value of 0.097 s-1. Meanwhile, 499.36 mg/L vanillyl alcohol was produced by COMT in vivo catalysis when fed with 1000 mg/L 3,4-dihydroxybenzyl alcohol. In the following experiment, de novo biosynthesis of vanillyl alcohol was carried out and 240.69 mg/L vanillyl alcohol was produced via modular optimization of pathway genes. This work was to date the first achievement for microbial production of vanillyl alcohol. Additionally, the present study demonstrates the application of enzyme promiscuity of COMT in the design of an artificial pathway for the production of high-value methylated aromatic compounds.

Correlation of Flavor Profile to Sensory Analysis of Bread Produced with Different Saccharomyces cerevisiae Originating from the Baking and Beverage Industry

Aroma is an important quality parameter for wheat bread, and most of the aroma compounds in yeast‐fermented bread are caused by the fermentative action of yeast. In this study, the impact of various strains of Saccharomyces cerevisiae, originating from the beverage industry, were investigated on the aroma profile of wheat bread. Seven volatiles were analyzed by gas chromatography–mass spectrometry after thermal desorption (GC‐MS TD) from the bread crumb. The results showed yeast strain‐dependent production of aroma compounds. Descriptive sensory analysis resulted in an overall taste acceptance by the panelists for breads baked with S. cerevisiae baker's yeast, T‐58, and Blanc. The panel acceptance can be explained by the production of sensory‐active compounds such as 3‐methyl‐1‐butanol and 2,3‐butandiol. Furthermore, the panelists preferred bread samples with a less bitter (r = –0.934, P &lt; 0.01) and less cheesy taste (r = –0.865, P &lt; 0.03). Also the visual aspects play an important role, shown by correlation between the specific volume and the overall appearance (r = 0.928, P &lt; 0.01). Aroma profile analysis offers a tool for the selection of new yeast strains, increasing the bread variety on the market. Consequently, aroma production as a yeast quality characteristic should be taken into account for the selection of new strains involved in breadmaking.

Products of hydrothermal treatment of lignin and the importance of ortho-directed repolymerization reactions

Alkaline hydrothermal treatment (HTT) of Protobind 1000 lignin was studied to improve the understanding of lignin conversion paths. HTT was performed at 300°C using NaOH as base catalyst. Product separation by acidification and solvent fractionation resulted in a liquid product of low molecular mass and narrow molecular mass distribution and two high molecular mass solid fractions. Twenty volatile compounds accounted for about 36wt% of the liquid product, however, the analysis by liquid injection GC–MS was estimated to detect only about 12wt% of the total products. Analytical pyrolysis was applied to investigate the pyrolyzable fraction of the liquid product and the high molecular mass fractions. The pyrolyzable mass accounted for 49wt% of the total products. The liquid product was quantitatively pyrolyzed at 500°C (91±10wt%) while less than half of the high molecular mass fractions were pyrolyzed. Several chemical features of the pyrolysates suggested that ortho-directed alkylation and condensation reactions of phenolate ions were important for the production of oligomeric and polymeric aromatic compounds during HTT. Increased abundancy of hydroxyphenyl and o-alkyl aromatic pyrolysates in the high molecular mass fractions suggested that the syringyl units of the raw lignin were less affected by repolymerization reactions than hydroxyphenyl and guaiacyl units. These results suggest that the monolignol composition of lignin is an important factor for the valorization of lignin by alkaline hydrothermal treatment.

Production of bioactive peptides from tomato seed isolate by Lactobacillus plantarum fermentation and enhancement of antioxidant activity

ABSTRACTTomato seed contains proteins of high nutritional value and nutraceutical properties, which can be recovered for application as food additives. In this study, we investigated the use of a Lactobacillus plantarum strain to obtain high-added-value peptides from the fermentation process using tomato seed meal extract as the substrate. Potentially tomato seed meal extract have antioxidant activity which is correlated to the amino acid structures, compositions and sequences. After 24 h of fermentation, the radical scavenging activity of the isolated extract was increased by 87%. The increase of antioxidant activity is potentially attributed to the production of different bioactive peptides bio transformed during fermentation. L. plantarum growth on tomato seed meal extract as substrate reduced content of crude and soluble proteins by 18.44% and 68.99%, respectively, after 24 h of fermentation. Gel filtration chromatography showed a depolymerization of high molecular weight of polymers. HPLC analysis showed a significant decrease in the concentration of total amino acids, especially glutamic acid and aspartic acid. FTIR results showed that the fermentation favors the production of new amides and aromatic compounds. The production of protease by L. plantarum was investigated and results showed that highest activity (401.45 U/ml) were obtained after 20 h of fermentation. Results confirmed that L. plantarum could degrade and convert tomato seed proteins into bioactive peptides that contributed positively to the improvement of antioxidant activity of the protein isolate.

De novo biosynthesis of trans-cinnamic acid derivatives in Saccharomyces cerevisiae.

The production of natural aroma compounds is an expanding field within the branch of white biotechnology. Three aromatic compounds of interest are cinnamaldehyde, the typical cinnamon aroma that has applications in agriculture and medical sciences, as well as cinnamyl alcohol and hydrocinnamyl alcohol, which have applications in the cosmetic industry. Current production methods, which rely on extraction from plant materials or chemical synthesis, are associated with drawbacks regarding scalability, production time, and environmental impact. These considerations make the development of a sustainable microbial-based production highly desirable. Through steps of rational metabolic engineering, we engineered the yeast Saccharomyces cerevisiae as a microbial host to produce trans-cinnamic acid derivatives cinnamaldehyde, cinnamyl alcohol, and hydrocinnamyl alcohol, from externally added trans-cinnamic acid or de novo from glucose as a carbon source. We show that the desired products can be de novo synthesized in S. cerevisiae via the heterologous overexpression of the genes encoding phenylalanine ammonia lyase 2 from Arabidopsis thaliana (AtPAL2), aryl carboxylic acid reductase (acar) from Nocardia sp., and phosphopantetheinyl transferase (entD) from Escherichia coli, together with endogenous alcohol dehydrogenases. This study provides a proof of concept and a strain that can be further optimized for production of high-value aromatic compounds.

Catabolic Pathway of Lignin Derived-Aromatic Compounds by Whole Cell of Phanerochaete chrysosporium (ATCC 20696) With Reducing Agent

Whole cell of Phanerochaete chrysosporium with reducing agent was applied to verify the degradation mechanism of aromatic compounds derived from lignin precisely. Unlike the free-reducing agent experiment, various degraded products of aromatic compounds were detected under the fungal treatment. Our results suggested that demethoxylation, <TEX>$C_{\alpha}$</TEX> oxidation and ring cleavage of aromatic compounds occurred under the catabolic system of P. chrysosporium. After that, degraded products stimulated the primary metabolism of fungus, so succinic acid was ultimately main degradation product of lignin derived-aromatic compounds. Especially, hydroquinone was detected as final intermediate in the degradation of aromatics and production of succinic acid. In conclusions, P. chrysosporium has an unique catabolic metabolism related to the production of succinic acid from lignin derived-aromatic compounds, which was meaningful in terms of lignin valorization.

3-P93-2 ゼオライト触媒を用いたユーカリの急速熱分解による芳香族化合物の製造(マテリアル原料化,Session 3 バイオマス等,ポスターセッション)

3-P93-2 ゼオライト触媒を用いたユーカリの急速熱分解による芳香族化合物の製造(マテリアル原料化,Session 3 バイオマス等,ポスターセッション)

O-19 グリーン芳香族化合物生産技術の開発(微生物利用の新展開,口頭セッション)

O-19 グリーン芳香族化合物生産技術の開発(微生物利用の新展開,口頭セッション)

Biotransformation of α- and β-pinene into flavor compounds

Products that bear the label "natural" have gained more attention in the marketplace. In this approach, the production of aroma compounds through biotransformation or bioconversion has been receiving more incentives in economic and research fields. Among the substrates used in these processes, terpenes can be highlighted for their versatility and low cost; some examples are limonene, α-pinene, and β-pinene. This work focused on the biotransformation of the two bicyclic monoterpenes, α-pinene and β-pinene; the use of different biocatalysts; the products obtained; and the conditions employed in the process.