Scent Production Research Articles

Transcriptome profiling provides new insights into the formation of floral scent in Hedychium coronarium.

BackgroundHedychium coronarium is a popular ornamental plant in tropical and subtropical regions because its flowers not only possess intense and inviting fragrance but also enjoy elegant shape. The fragrance results from volatile terpenes and benzenoids presented in the floral scent profile. However, in this species, even in monocots, little is known about the underlying molecular mechanism of floral scent production.ResultsUsing Illumina platform, approximately 81 million high-quality reads were obtained from a pooled cDNA library. The de novo assembly resulted in a transcriptome with 65,591 unigenes, 50.90 % of which were annotated using public databases. Digital gene expression (DGE) profiling analysis revealed 7,796 differential expression genes (DEGs) during petal development. GO term classification and KEGG pathway analysis indicated that the levels of transcripts changed significantly in “metabolic process”, including “terpenoid biosynthetic process”. Through a systematic analysis, 35 and 33 candidate genes might be involved in the biosynthesis of floral volatile terpenes and benzenoids, respectively. Among them, flower-specific HcDXS2A, HcGPPS, HcTPSs, HcCNL and HcBCMT1 might play critical roles in regulating the formation of floral fragrance through DGE profiling coupled with floral volatile profiling analyses. In vitro characterization showed that HcTPS6 was capable of generating β-farnesene as its main product. In the transcriptome, 1,741 transcription factors (TFs) were identified and 474 TFs showed differential expression during petal development. It is supposed that two R2R3-MYBs with flower-specific and developmental expression might be involved in the scent production.ConclusionsThe novel transcriptome and DGE profiling provide an important resource for functional genomics studies and give us a dynamic view of biological process during petal development in H. coronarium. These data lay the basis for elucidating the molecular mechanism of floral scent formation and regulation in monocot. The results also provide the opportunities for genetic modification of floral scent profile in Hedychium.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1653-7) contains supplementary material, which is available to authorized users.

Non-Conventional Yeasts Whole Cells as Efficient Biocatalysts for the Production of Flavors and Fragrances.

The rising consumer requests for natural flavors and fragrances have generated great interest in the aroma industry to seek new methods to obtain fragrance and flavor compounds naturally. An alternative and attractive route for these compounds is based on bio-transformations. In this review, the application of biocatalysis by Non Conventional Yeasts (NCYs) whole cells for the production of flavor and fragrances is illustrated by a discussion of the production of different class of compounds, namely Aldehydes, Ketones and related compounds, Alcohols, Lactones, Terpenes and Terpenoids, Alkenes, and Phenols.

Aislamiento de una bacteria endófita de vainilla (Vanilla planifolia) con actividad biocontroladora in vitro contra Fusarium oxysporum f. sp. Vanillae

<p class="p1">El género <em>Vanilla </em>pertenece a la familia Orchidaceae. Algunas de sus especies con interés comercial son <em>V. planifolia</em>, <em>V. pompona </em>y <em>V. tahitensis</em>. La clasificación de la calidad de la vainilla se efectúa según el largo de la cápsula y el contenido de vainillina, la cual se utiliza para elaborar alimentos y bebidas, como materia prima en la industria farmacéutica y en la producción de cosméticos y perfumes, entre otros usos. Se considera que el mayor problema que enfrenta la producción de vainilla es la pudrición de la raíz ocasionada por el hongo <em>Fusarium oxyporum </em>f. sp. Vanillae, que provoca entre 30-52% de la muerte de las plantas al atacar las raíces adventicias, impidiéndoles absorber agua y nutrientes. El hongo no puede erradicarse por la acción de agroquímicos ya que dañan la viabilidad de las plantas; además, el cultivo de vainilla sin la aplicación de agroquímicos de manera orgánica en sistemas agroforestales es una actividad que está cobrando gran interés entre los pequeños productores del país. Es por tal razón que en esta investigación se evaluó la capacidad de control de bacterias endófitas aisladas de muestras de vainilla procedentes de Corcovado, Puriscal, Dota y Guápiles, mediante pruebas de antagonismo in vitro entre la bacterias aisladasy el hongo <em>F. oxysporum</em>. El resultado es que la cepa bacteriana B1M11 es una candidata promisoria para responder al ataque del patógeno<em>, </em>lo que se corroboró con la aparición de un halo de inhibición del crecimiento del hongo en placa. </p>

Engineers of scent

Companies exploring biotech approaches to flavor and fragrance production must navigate challenges in regulations, market dynamics and public perception. Emily Waltz investigates.

Timing is Everything: Temporal Variation in Floral Scent, and its Connections to Pollinator Behavior and Female Reproductive Success in Phlox divaricata

The study of floral traits and pollination for the plant genus Phlox has historically been focused on either surveys of general pollinator affinities across the genus or detailed research on pollinator-mediated evolution of floral color in a single species (Phlox drummondii). The purpose of this study was to explore a different kind of trait – floral scent – in Phlox divaricata, a species noted for its strong scent. Specifically, we predicted the diel emission patterns of floral scent might covary with the daily abundance of diurnal moths, identified in a previous study as the most important pollinators in a Konza Prairie population of P. divaricata. Consistent with this prediction, we documented peaks in median floral scent emissions at 1000–1200 and 1930–2130, coinciding with peaks in moth visitation and resulting seed production. Two groups of scent compounds contributed to this pattern; linalool and its associated lilac aldehyde/alcohol compounds (especially lilac aldehyde B) contributed a greater proportion to scent at 1000–1200, while aromatic compounds (including benzaldehyde and benzyl acetate) contributed a greater proportion to scent at 1930–2130 and other afternoon time periods. These volatiles are known floral attractants for several lepidopteran pollinators, including noctuid moths. However, there is an additional peak in pollinator abundance (Hemaris diurnal hawkmoths) and seed set at a time when scent production is relatively low (1400–1600) suggesting additional factors mediate both pollinator behavior and floral volatile emissions. Future studies of P. divaricata should test for the presence of destructive floral enemies that might be attracted by floral volatiles during mid-afternoon periods, as well as the importance of visual floral traits (color, shape) in attracting diurnal moths, an important functional group of pollinators that has received minimal attention in North America.

Volatile emissions from common consumer products

Consumer products emit a range of volatile organic compounds (VOCs) that can affect air quality and health. Risk reduction is hindered because of lack of information about specific product emissions. This study investigates and compares VOCs emitted from 37 common products (air fresheners, laundry products, cleaners, and personal care products), including those with certifications and claims of green and organic. It extends a prior study of 25 consumer products by adding 12 more products, including fragrance-free versions of fragranced products, representing the first such comparison in the scientific literature. This study found 156 different VOCs emitted from the 37 products, with an average of 15 VOCs per product. Of these 156 VOCs, 42 VOCs are classified as toxic or hazardous under US federal laws, and each product emitted at least one of these chemicals. Emissions of carcinogenic hazardous air pollutants (HAPs) from green fragranced products were not significantly different from regular fragranced products. The most common chemicals in fragranced products were terpenes, which were not in fragrance-free versions. Of the volatile ingredients emitted, fewer than 3 % were disclosed on any product label or material safety data sheet (MSDS). Because health effects depend on many factors, not only individual ingredients, this study makes no claims regarding possible risks. However, knowledge of product composition can be an important step to understand, assess, and reduce potential exposures and effects.

Transcriptome analysis of thermogenic Arum concinnatum reveals the molecular components of floral scent production.

Several plant species can generate enough heat to increase their internal floral temperature above ambient temperature. Among thermogenic plants, Arum concinnatum shows the highest respiration activity during thermogenesis. However, an overall understanding of the genes related to plant thermogenesis has not yet been achieved. In this study, we performed de novo transcriptome analysis of flower organs in A. concinnatum. The de novo transcriptome assembly represented, in total, 158,490 non-redundant transcripts, and 53,315 of those showed significant homology with known genes. To explore genes associated with thermogenesis, we filtered 1266 transcripts that showed a significant correlation between expression pattern and the temperature trend of each sample. We confirmed five putative alternative oxidase transcripts were included in filtered transcripts as expected. An enrichment analysis of the Gene Ontology terms for the filtered transcripts suggested over-representation of genes involved in 1-deoxy-d-xylulose-5-phosphate synthase (DXS) activity. The expression profiles of DXS transcripts in the methyl-d-erythritol 4-phosphate (MEP) pathway were significantly correlated with thermogenic levels. Our results suggest that the MEP pathway is the main biosynthesis route for producing scent monoterpenes. To our knowledge, this is the first report describing the candidate pathway and the key enzyme for floral scent production in thermogenic plants.

Selective preparation of campholenic aldehyde over heterogenized methyltrioxorhenium

The presented report focuses on the isomerization of α-pinene oxide over methyltrioxorhenium (MTO) immobilized on a range of mesoporous materials with different SiO2/Al2O3 ratios, namely mesoporous alumina (m-Al2O3), aluminosilicates type Siral (with Al content 60–80 %), silica and MCM-41 or in its homogeneous form. Optimization of MTO immobilization has been studied and published previously. α-Pinene oxide, an oxygenated derivative of α-pinene, isomerizes rapidly into various valuable substances useful as flavors, fragrances and pharmaceutical compounds. Campholenic aldehyde is the one of the most desired products of α-pinene oxide isomerization, being a valuable intermediate for the production of sandalwood-like fragrances. The prepared catalytic systems were successfully used for selective preparation of campholenic aldehyde. Homogeneous and heterogenized MTO showed very high activity in α-pinene oxide isomerization (100 % conversion within a few minutes) and very high selectivity to campholenic aldehyde, amounting to over 80 %. Furthermore, the possibility of catalyst regeneration was proven.

Past Scents: Historical Perspectives on Smell. By Jonathan Reinarz (Urbana, University of Illinois Press, 2014) 296 pp. $90.00 cloth $25.00 paper

Reinarz’s Past Scents aims to offer a “comprehensive and coherent introduction to the history of smell” (1), a subject usually defined by its ephemerality, diffusiveness, and visceral impact rather than its cultural or historical significance. Its challenge to the traditional history of olfaction more than hits the mark, presenting not only a rich overview of the cultural history of olfaction but also a compelling synthesis of historiographical approaches to this topic and a sharp summary of the state of the field. Reinarz draws extensively from recent work while also expanding its purview to include the insights of anthropologists, literary scholars, classicists, art historians, and sociologists, as well as insights from the history of medicine. The strength of the book lies in its interdisciplinary and transtemporal approach; that Reinarz can achieve such breadth without sacrificing the variances inherent in this topic is a real achievement. The result is a comprehensive, coherent, and accessible introduction to the subject that deserves a wide audience.Aligning himself with the argument that the senses are cultural phenomena, Reinarz organizes the book into six chapters that explore the social ramifications of past definitions of the science of smell. To ask who or what smelled in the past, as Reinarz says, is never a neutral question: As the famous nineteenth-century perfumer Edward Rimmel put it, “The history of perfume, in some manner, is the history of civilization” (1). Reinarz’s book seizes on the associative links embedded in such a claim in order to undo its logic. To understand the subject and objects of smell in the past is to grapple with the cultural history of “civilizations,” including those that have been explicitly excluded from such constructions. Among other things, Reinarz traces the use of scents in shaping cultural meanings of religion, luxury, race, gender, class, and a growing sense of urban spheres.After a useful overview of various medical theories of olfaction in the introduction, the first chapter examines smell’s role in religion, focusing on the fourth century c.e. (when early Christians first embraced ancient links between fragrance and worshipping the divine); the second chapter, about “fragrant lucre” and the perfume trade, delves more deeply into how liturgical practices inspired a burgeoning perfume trade in medieval and early modern Europe. Chapter 2 surveys how scent ingredients emerged as lucrative objects of exchange, in part because of a growing belief in their medicinal efficacy. How one smelled was linked to one’s health.The next three chapters demonstrate, however, that medicinal constructions of bodily smell often provided a ready rationale for social exclusion under the aegis of public health. Reinarz offers three cogent case studies about (1) the role of smell in constructing a “foul” and “fragrant” other; (2) the role of olfaction in shaping histories of racial difference (in medieval Europe as well as in nineteenth- and twentieth-century America) and gender (vis-à-vis trenchant and misogynist constructions of the smell of women’s bodies in both European medical histories and gendered histories of the production and consumption of perfume); and (3) the role of class (in charting the rise of deodorization as a marker during the nineteenth century). In the final chapter, Reinarz shifts gears, examining the spatial ramifications of such olfactory histories on urban life. The smells of the city reflect its changing composition, as well as the structural challenges that it faced due to population density. For this reason, scholars are now using smells to construct new kinds of “maps” of urban space, pushing against a teleology of civilization aligned with deodorization.This book suggests that engagement with the cultural work of smell both in the past and in the present can be richly rewarding. Reinarz’s timely survey of historical perspectives on smell will (hopefully) inspire further research that will move us beyond simple binaries of fragrant/foul and self/other toward more redolent possibilities.

Determinants of exposure to fragranced product chemical mixtures in a sample of twins.

Fragranced product chemical mixtures may be relevant for environmental health, but little is known about exposure. We analyzed results from an olfactory challenge with the synthetic musk fragrance 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopento-γ-2-benzopyran (HHCB), and a questionnaire about attitudes toward chemical safety and use of fragranced products, in a sample of 140 white and 17 black twin pairs attending a festival in Ohio. Data for each product were analyzed using robust ordered logistic regressions with random intercepts for “twin pair” and “sharing address with twin”, and fixed effects for sex, age, education, and “ever being bothered by fragrances”. Due to the small number of black participants, models were restricted to white participants except when examining racial differences. Overall patterns of association were summarized across product-types through random-effects meta-analysis. Principal components analysis was used to summarize clustering of product use. The dominant axis of variability in fragranced product use was “more vs. less”, followed by a distinction between household cleaning products and personal care products. Overall, males used fragranced products less frequently than females (adjusted proportionate odds ratio 0.55, 95% confidence interval 0.33, 0.93). This disparity was driven by personal care products (0.42, 95% CI: 0.19, 0.96), rather than household cleaning products (0.79, 95% CI: 0.49, 1.25) and was particularly evident for body lotion (0.12, 95% CI: 0.05, 0.27). Overall usage differed by age (0.64, 95% CI: 0.43, 0.95) but only hand soap and shampoo products differed significantly. “Ever being bothered by fragrance” had no overall association (0.92, 95% CI: 0.65, 1.30) but was associated with laundry detergent use (0.46, 95% CI: 0.23, 0.93). Similarly, black vs. white differences on average were not significant (1.34, 95% CI: 0.55, 3.28) but there were apparent differences in use of shampoo (0.01, 95% CI: 0.00, 0.69), body lotion (4.67, 95% CI: 1.18, 18.47), and perfume (6.22, 95% CI:1.08, 35.89). There was no overall association with thinking about product risks (0.90, 95% CI: 0.79, 1.02), nor with inability to smell HHCB (0.84, 95% CI: 0.63, 1.12). Exposure to fragranced products may differ demographically. The relevance for health disparities should be studied.

Petunia × hybrida floral scent production is negatively affected by high-temperature growth conditions.

Increasing temperatures due to changing global climate are interfering with plant-pollinator mutualism, an interaction facilitated mainly by floral colour and scent. Gas chromatography-mass spectroscopy analyses revealed that increasing ambient temperature leads to a decrease in phenylpropanoid-based floral scent production in two Petunia × hybrida varieties, P720 and Blue Spark, acclimated at 22/16 or 28/22 °C (day/night). This decrease could be attributed to down-regulation of scent-related structural gene expression from both phenylpropanoid and shikimate pathways, and up-regulation of a negative regulator of scent production, emission of benzenoids V (EOBV). To test whether the negative effect of increased temperature on scent production can be reduced in flowers with enhanced metabolic flow in the phenylpropanoid pathway, we analysed floral volatile production by transgenic 'Blue Spark' plants overexpressing CaMV 35S-driven Arabidopsis thaliana production of anthocyanin pigments 1 (PAP1) under elevated versus standard temperature conditions. Flowers of 35S:PAP1 transgenic plants produced the same or even higher levels of volatiles when exposed to a long-term high-temperature regime. This phenotype was also evident when analysing relevant gene expression as inferred from sequencing the transcriptome of 35S:PAP1 transgenic flowers under the two temperature regimes. Thus, up-regulation of transcription might negate the adverse effects of temperature on scent production.

A Biotechnological Approach to Microbial Based Perfumes and Flavours

Flavours and fragrances represent over a quarter of the world market and most of the flavouring and perfume compounds are produced through chemical synthesis or by extraction from natural materials like plant and animal sources. Fragrances and flavours finds application in food, feed, cosmetic, chemical and pharmaceutical industries. Plant and animal sources are an important source of bioflavours but these bioactive compounds are present in minor quantities thus making their isolation and formulation very expensive. The other bio-route for flavour synthesis is based on de novo microbial processes (fermentation) or on bioconversions of natural precursors using microbial cells or enzymes (biocatalysis). This mini review is an attempt to focus on the potential of microorganisms to be used as small biofactories for the production of bio-flavours and fragrances.

ВЛИЯНИЕ ФАКТОРОВ ФИЗИЧЕСКОЙ ПРИРОДЫ НА СКОРОСТЬ ПРОТЕКАНИЯ ПРОЦЕССОВ ЧЕРСТВЕНИЯ ХЛЕБА

The possibility of using different methods of influence to improve the quality and persistence of bakery products. The quality of bread and bakery products, which are highly labile products during storage is significantly reduced. Loss of fresh bread and bakery products - is the result of complex biochemical, physical, chemical and colloidal processes that are linked to changes in proteins and carbohydrates, as well as reduce weight due to loss of moisture and volatile matter. The results of these processes are associated with the loss of softness and elasticity of the crumb, increase its friability, loss of taste and fragrance products, which generally determines the loss of consumer product value. Costs for bread is 24 hours, it is believed that during that time capable to keep the bread fresh product attributes. Since it is the freshness factor determining consumer preferences for bread, the increase in terms of sales and storage of grain is a priority task for the baking industry. The need to study the process of staling, the factors determining them, and find ways to preserve the freshness of bread determines the relevance of this work. One possible way to improve the quality and persistence of bread and bakery products is the use of activated water, which are devoted to research data. The article presents the results of the influence of water, activated by various physical and chemical methods, the quality of semi-finished and finished products. The effect of activated water on the process of baking, as well as a change in the basic indicators of the quality of grain during storage.

TOWARDS THE ROSE GENOME SEQUENCE AND ITS USE IN RESEARCH AND BREEDING

Rose is one of the most economically important ornamental crops worldwide. Rosa sp. can become a model for woody ornamentals. Its genome size is relatively small (560 Mb), its genetic history with ploidy events is well documented, and rose has a short life for a woody plant. Furthermore, different tools are available, including transcriptomic tools, genetic maps and genetic transformation protocols. Rose represents an original model for studying some ornamental traits that cannot be addressed in other model plant species such as Arabidopsis. Some of these traits, such recurrent blooming, flower morphogenesis or scent production and emission, are of economic interest. Different groups involved in rose genetics and genomics gathered to form the ‘Rose Genome Sequence Initiative’. Our objective is to obtain a high quality rose genome sequence of the diploid R. chinensis ‘Old Blush’. One important issue is the high level of heterozygosity of roses. To tackle this issue, different strategies are proposed: production of a haploid and development a high density genetic map to anchor the genome. This genetic map will be developed from a cross between ‘Old Blush’ and R. wichurana. The genotype R. chinensis ‘Old Blush’ will be sequenced using NGS technologies. The data will be assembled and arranged using the high-density map. In order to increase ESTs and to facilitate genome annotation, we have recently produced ESTs from various tissues of ‘Old Blush’ under different conditions. Digital expression (RNA Seq) was obtained from the different tissues and data are available on the following web site (https:// iant.toulouse.inra.fr/plants/rosa/FATAL/). The rose genome sequence will be a great step to help identifying the molecular basis of ornamental traits and also to study genetic diversity and genome evolution in the genus Rosa and in the Rosaceae family

Cloning and characterization of a benzoic acid/salicylic acid carboxyl methyltransferase gene involved in floral scent production from lily (Lilium 'Yelloween').

In lily flowers, the volatile ester methyl benzoate is one of the major and abundant floral scent compounds; however, knowledge regarding the biosynthesis of methyl benzoate remains unknown for Lilium. In this study, we isolated a benzoic acid/salicylic acid carboxyl methyltransferase (BSMT) gene, LiBSMT, from petals of Lilium 'Yelloween'. The gene has an open reading frame of 1083 base pairs (bp) and encodes a protein of 41.05 kDa. Sequence alignment and phylogenetic analyses of LiBSMT revealed 40-50% similarity with other known benzenoid carboxyl methyltransferases in other plant species, and revealed homology to BSMT of Oryza sativa. Heterologous expression of this gene in Escherichia coli yielded an enzyme responsible for catalyzing benzoic acid and salicylic acid to methyl benzoate and methyl salicylate, respectively. Quantitative real-time polymerase chain reaction analysis showed that LiBSMT was preferentially expressed in petals. Moreover, the expression of LiBSMT in petals was developmentally regulated. These expression patterns correlate well with the emission of methyl benzoate. Our results indicate that LiBSMT plays an important role in floral scent methyl benzoate production and emission in lily flowers.

Experimental evidence for specialized bird pollination in the endangered South African orchidSatyrium rhodanthumand analysis of associated floral traits

The bird pollination syndrome is characterized by red, unscented flowers with dilute nectar in long nectar tubes. However, the extent to which plants with such traits actually depend on birds for seed production is seldom determined experimentally, and traits such as colour and scent production are often assessed only subjectively. We documented bird pollination and quantified floral traits in the critically endangered Satyrium rhodanthum (Orchidaceae) from mistbelt grasslands in the summer-rainfall region of South Africa. Direct observations and motion trigger camera footage revealed amethyst sunbirds as the only pollinators, despite the presence of other potential pollinators. Experimental exclusion of sunbirds significantly reduced pollination and fruit set to near zero. Pollination success in naturally pollinated plants was close to 100% in one year, and fruit set varied from 23 to 64% in other years. Pollen transfer efficiency was 5.8%, which is lower than in related insect-pollinated species, probably due to a tendency of birds to wipe pollinaria from their beak. Flowers of S. rhodanthum only reflect light in the red range of the spectrum, and they produce only a few aliphatic and monoterpene scent compounds at comparatively low emission rates. Nectar volume and sugar concentration varied between 2.7 and 3.7 μL and 23.7 and 25.9%, respectively. We conclude that S. rhodanthum is highly specialized for pollination by sunbirds. Colour, scent and nectar characteristics differ from insect-pollinated Satyrium species and are consistent with those expected for bird-pollinated flowers, and may contribute to lack of visitation by other potential long-tongued pollinators. Habitat loss probably underlies the critically endangered conservation status of S. rhodanthum, but the specialization for pollination by a single bird species means that reproduction in this orchid is vulnerable to losses in surrounding communities of plants that subsidize the energetic requirements of sunbirds. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 177, 141–150.

Cell factory applications of the yeast Kluyveromyces marxianus for the biotechnological production of natural flavour and fragrance molecules.

Kluyveromyces marxianus is emerging as a new platform organism for the production of flavour and fragrance (F&F) compounds. This food-grade yeast has advantageous traits, such as thermotolerance and rapid growth, that make it attractive for cell factory applications. The major impediment to its development has been limited fundamental knowledge of its genetics and physiology, but this is rapidly changing. K. marxianus produces a wide array of volatile molecules and contributes to the flavour of a range of different fermented beverages. Advantage is now being taken of this to develop strains for the production of metabolites such as 2-phenylethanol and ethyl acetate. Strains that were selected from initial screens were used to optimize processes for production of these F&F molecules. Most developments have focused on optimizing growth conditions and the fermentation process, including product removal, with future advancement likely to involve development of new strains through the application of evolutionary or rational engineering strategies. This is being facilitated by new genomic and molecular tools. Furthermore, synthetic biology offers a route to introduce new biosynthetic pathways into this yeast for F&F production. Consumer demand for biologically-synthesized molecules for use in foods and other products creates an opportunity to exploit the unique potential of K. marxianus for this cell factory application.

Impact of room fragrance products on indoor air quality

Everyday life can no longer be imagined without fragrances and scented products. For the consumer, countless products exists which are solely or partly intended to give off a certain scent in sufficient concentrations to odorize a complete room. Sprays, diffusers and evaporators, scented candles and automatic devices for the distribution of fragrance liquids are typical examples of such products. If the consumer uses such products, his consent to the release of certain chemicals in his home can be implied, however, he may not know what kind of fragrance substances and solvents will be present in which concentrations.In this study, we determined the volatile emissions of a number of fragrance products in detail. Measurements were carried out under controlled conditions in test chambers. The products were tested in a passive (unused) and an active state, wherever applicable. Following a defined test protocol, the release of volatile organic compounds, ultrafine particles and NOx was monitored for each product. The potential for forming secondary organic aerosols under the influence of ozone was studied, and for a selection of products the long-term emission behavior was assessed. A remarkable variety of fragrance substances was found and more than 100 relevant compounds were identified and quantified. While it is the intended function of such products to release fragrance substances, also considerable amounts of non-odorous solvents and by-products were found to be released from several air fresheners. Emissions rates exceeding 2 mg/(unit*h) were measured for the five most common solvents.

Biodiversity of major bacterial groups in association with agarwood (Aquilaria crassna) in Khanh Hoa province, Vietnam

Agarwood mainly formed by Aquilaria species is an economically and pharmaceutically important natural product used for the production of incense, perfumes and traditional medicines in Asia. Endophytic bacteria are potentially important in producing pharmaceutical compounds found in the plants. The aim of this research is to isolate, classify and identify major endophytic bacteria groups associated with agarwood of Aquilaria crassna species in Khanh Hoa province, Vietnam. Agarwood samples were collected and surface-sterilized, and total endophytic bacteria were isolated on Tryptic Soy Agar by the spread plate method. Major bacterial groups were classified according to the Bergey’s system. The 16S rRNA gene fragments were amplified using PCR method, and bacterial isolates were identified using this gene sequence similarity based method. The results showed that from 0.121 g of agarwood, total 26 bacterial isolates were purified and divided into 7 separated groups, in which the group II of Gram-positive spore-forming bacteria was the most dominant. Especially, two dominant strains, T14 of group II, and T15 of group VII, were identified as Bacillus pumilus and Alcaligenes faecalis, respectively. To our knowledge, it is the first time that biodiversity of bacterial endophytes associated with agarwood from Aquilaria crassna in Vietnam has been reported, which requires of further study to understand the relationship of endophytic bacteria to agarwood-producing Aquilaria crassna species as well as explore their potential applications towards the development of valuable bioactive compounds.
 Trầm hương, chủ yếu được tạo ra từ các loài cây Dó (Aquilaria), là một sản phẩm tự nhiên có giá trị kinh tế và y học đã được sử dụng để sản xuất hương, nước hoa và các dược phẩm truyền thống ở châu Á. Vi khuẩn nội cộng sinh thực vật được cho là một nguồn quan trọng cho các dược phẩm có nguồn gốc thực vật. Mục tiêu của nghiên cứu này là nhằm phân lập, phân loại và định danh các nhóm vi khuẩn chính trên Trầm hương Khánh Hòa, Việt Nam. Các mẫu Trầm hương được thu nhận và vô trùng bề mặt dùng để phân lập vi khuẩn tổng số trên môi trường TSA bằng phương pháp trải đĩa. Các nhóm vi khuẩn chính được phân loại dựa theo hệ thống chuẩn Bergey. Đoạn gen mã hóa 16S rRNA được khuếch đại bằng phương pháp PCR, và các chủng vi khuẩn được định danh bằng phép so sánh độ tương đồng trình tự của đoạn gen này. Kết quả cho thấy từ 0,121 g mẫu trầm hương, chúng tôi đã phân lập được 26 chủng vi khuẩn và phân chúng vào 7 nhóm chính, trong đó nhóm II bao gồm các vi khuẩn Gram dương sinh bào tử là nhóm chiếm ưu thế nhất. Đặc biệt, có 2 chủng ưu thế là chủng T14 thuộc nhóm II và chủng T15 thuộc nhóm VII đã được định danh tương ứng là Bacillus pumilus và Alcaligenes faecalis. Đây là nghiên cứu đầu tiên về đa dạng sinh học của các nhóm vi khuẩn chính trên Trầm hương Khánh Hòa. Vì vậy, cần có những nghiên cứu tiếp theo nhằm tìm hiểu mối quan hệ giữa các vi khuẩn nội cộng sinh với cây Dó bầu (Aquilaria crassna) tạo trầm cũng như khai thác những ứng dụng tiềm năng của các vi khuẩn này theo hướng phát triển các hoạt chất sinh học có giá trị.

Influence of carbon and nitrogen source on production of volatile fragrance and flavour metabolites by the yeast Kluyveromyces marxianus.

The yeast Kluyveromyces marxianus produces a range of volatile molecules with applications as fragrances or flavours. The purpose of this study was to establish how nutritional conditions influence the production of these metabolites. Four strains were grown on synthetic media, using a variety of carbon and nitrogen sources and volatile metabolites analysed using gas chromatography-mass spectrometry (GC-MS). The nitrogen source had pronounced effects on metabolite production: levels of the fusel alcohols 2-phenylethanol and isoamyl alcohol were highest when yeast extract was the nitrogen source, and ammonium had a strong repressing effect on production of 2-phenylethyl acetate. In contrast, the nitrogen source did not affect production of isoamyl acetate or ethyl acetate, indicating that more than one alcohol acetyl transferase activity is present in K. marxianus. Production of all acetate esters was low when cells were growing on lactose (as opposed to glucose or fructose), with a lower intracellular pool of acetyl CoA being one explanation for this observation. Bioinformatic and phylogenetic analysis of the known yeast alcohol acetyl transferases ATF1 and ATF2 suggests that the ancestral protein Atf2p may not be involved in synthesis of volatile acetate esters in K. marxianus, and raises interesting questions as to what other genes encode this activity in non-Saccharomyces yeasts. Identification of all the genes involved in ester synthesis will be important for development of the K. marxianus platform for flavour and fragrance production.