During brewery handling, production strains of yeast must respond to fluctuations in dissolved oxygen concentration, pH, osmolarity, ethanol concentration, nutrient supply and temperature. Fermentation performance of brewing yeast strains is dependent on their ability to adapt to these changes, particularly during batch brewery fermentation which involves the recycling (repitching) of a single yeast culture (slurry) over a number of fermentations (generations). Modern practices, such as the use of high-gravity worts and preparation of dried yeast for use as an inoculum, have increased the magnitude of the stresses to which the cell is subjected. The ability of yeast to respond effectively to these conditions is essential not only for beer production but also for maintaining the fermentation fitness of yeast for use in subsequent fermentations. During brewery handling, cells inhabit a complex environment and our understanding of stress responses under such conditions is limited. The advent of techniques capable of determining genomic and proteomic changes within the cell is likely vastly to improve our knowledge of yeast stress responses during industrial brewery handling.
If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services. AbstractPurpose -The purpose of this paper is to identify the realignment of the physical distribution process for store-based retailers in their efforts to integrate the online channel into their business model. Multiple attributes of the physical distribution process are evaluated to identify associations with order fulfillment methods adopted by omni-channel retailers. Design/methodology/approach -A multi-method approach is used which includes qualitative evaluation of 50 interviews of supply chain executives from large retailers. Additionally, secondary data about firm size, store and distribution networks, online sales, distribution configuration, and order delivery options are used. The findings of qualitative analysis are incorporated into a quantitative classification-tree analysis to identify associations among distribution attributes, order fulfillment methods and order delivery services. Findings -Retailers are developing a consistent omni-channel physical distribution process in which stores undertake a bigger role in order fulfillment and delivery. Level of online sales, size of distribution network, number of sales associates at a store, and number of years engaged in the online channel are identified as having strong associations with the type of order fulfillment method used by omni-channel retailers. The study finds that retailers are focussed on integrating their store and DC inventories and have the benefit of scale with a large store network. Practical implications -Retailers are reconfiguring their physical distribution processes in the complex omni-channel environment can use the findings of this study to evaluate their strategy and identify the level of realignment effort that is needed. A better understanding of the requirements of physical distribution in an omni-channel setting will guide retailers in developing requisite operational capabilities. Originality/value -This paper provides a first in-depth look at order fulfillment choices in omni-channel retail and identifies efforts that are underway to realign key elements of the physical distribution process.
The interspecific hybrid Saccharomyces pastorianus is the most commonly used yeast in brewery fermentations worldwide. Here, we generated de novo lager yeast hybrids by mating a domesticated and strongly flocculent Saccharomyces cerevisiae ale strain with the Saccharomyces eubayanus type strain. The hybrids were characterized with respect to the parent strains in a wort fermentation performed at temperatures typical for lager brewing (12 °C). The resulting beers were analysed for sugar and aroma compounds, while the yeasts were tested for their flocculation ability and α-glucoside transport capability. These hybrids inherited beneficial properties from both parent strains (cryotolerance, maltotriose utilization and strong flocculation) and showed apparent hybrid vigour, fermenting faster and producing beer with higher alcohol content (5.6 vs 4.5 % ABV) than the parents. Results suggest that interspecific hybridization is suitable for production of novel non-GM lager yeast strains with unique properties and will help in elucidating the evolutionary history of industrial lager yeast.Electronic supplementary materialThe online version of this article (doi:10.1007/s10295-015-1597-6) contains supplementary material, which is available to authorized users.
Two distinct genetic groups (Saaz and Frohberg) exist within the hybrid Saccharomyces pastorianus (S. cerevisiae Â S. eubayanus) taxon. However, physiological/technological differences that exist between the two groups are not known. Fermentative capability of the parental S. eubayanus has likewise never been studied. Here, 58 lager strains were screened to determine which hybrid group they belonged to, and selected strains were characterized to determine salient characteristics. In 15 P all-malt wort fermentations at 22 C, Frohberg strains showed greater growth and superior fermentation (80% apparent attenuation, 6.5% alcohol by volume in 3-4 days) compared to all other strains and maintained highest viability values (>93%). Fermentation with S. eubayanus was poor at the same temperature (33% apparent attenuation, 2.7% alcohol by volume at 6 days and viability reduced to 75%). Saaz strains and S. eubayanus were the least sensitive to cold (10 C), though this did not translate to greater fermentation performance. Fermentation with S. eubayanus was poor at 10 C but equal to or greater than that of the Saaz strains. Performance of Saaz yeast/S. eubayanus was limited by an inability to use wort maltotriose. [ 14 C]-Maltotriose transport assays also showed negligible activity in these strains (≤0.5 mmol min À1 g À1 dry yeast). Beers from Saaz fermentations were characterized by two-to sixfold lower production of the flavour compounds methyl butanol, ethyl acetate and 3-methylbutyl acetate compared to Frohberg strains. Higher alcohol and ester production by S. eubayanus was similar to that of Frohberg strains.
The genomes of hybrid organisms, such as lager yeast (Saccharomyces cerevisiae × Saccharomyces eubayanus), contain orthologous genes, the functionality and effect of which may differ depending on their origin and copy number. How the parental subgenomes in lager yeast contribute to important phenotypic traits such as fermentation performance, aroma production, and stress tolerance remains poorly understood. Here, three de novo lager yeast hybrids with different ploidy levels (allodiploid, allotriploid, and allotetraploid) were generated through hybridization techniques without genetic modification. The hybrids were characterized in fermentations of both high gravity wort (15 °P) and very high gravity wort (25 °P), which were monitored for aroma compound and sugar concentrations. The hybrid strains with higher DNA content performed better during fermentation and produced higher concentrations of flavor-active esters in both worts. The hybrid strains also outperformed both the parent strains. Genome sequencing revealed that several genes related to the formation of flavor-active esters (ATF1, ATF2¸ EHT1, EEB1, and BAT1) were present in higher copy numbers in the higher ploidy hybrid strains. A direct relationship between gene copy number and transcript level was also observed. The measured ester concentrations and transcript levels also suggest that the functionality of the S. cerevisiae- and S. eubayanus-derived gene products differs. The results contribute to our understanding of the complex molecular mechanisms that determine phenotypes in lager yeast hybrids and are expected to facilitate targeted strain development through interspecific hybridization.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-016-7588-3) contains supplementary material, which is available to authorized users.
Immobilized cell technology has shown a significant promotional effect on the fermentation of alcoholic beverages such as beer, wine and cider. However, genetic, morphological and physiological alterations occurring in immobilized yeast cells impact on aroma formation during fermentation processes. The focus of this review is exploitation of existing knowledge on the biochemistry and the biological role of flavour production in yeast for the biotechnological production of aroma compounds of industrial importance, by means of immobilized yeast. Various types of carrier materials and immobilization methods proposed for application in beer, wine, fruit wine, cider and mead production are presented. Engineering aspects with special emphasis on immobilized cell bioreactor design, operation and scale-up potential are also discussed. Ultimately, examples of products with improved quality properties within the alcoholic beverages are addressed, together with identification and description of the future perspectives and scope for cell immobilization in fermentation processes.
In this day and age of re-engineering, lean inventories and global competition many firms are concentrating their efforts on core activities that are critical to survival. This shift in business strategy is stimulating the demand for logistics management and operating services provided by third-party sources. While individual distribution functions such as transportation, warehousing, and freight bill payment have long been provided by outside suppliers, the procurement of "bundled" services, managed by external professionals, is somewhat new to the USA. Also, a growing number of firms are seeking to differentiate themselves from their competitors via the provision of superior logistical support services. These services are increasingly being provided and directed by external suppliers. Apart from a growing interest in integrated supply chain management, another topic of great interest to logistics today is the use of contract or third-party services. BackgroundCurrent business trends indicate the market for third-party logistics is poised for substantial growth. According to several industry observers, the overall revenues for third-party logistics services are expected to expand from approximately $15 billion in 1994 to $50 billion annually by the year 2000 [1,2]. New suppliers, many representing alliances between existing transportation, warehousing and information providers, are continually entering the market.A fair characterization of the market for third-party logistics services indicates that the industry is in the "introduction-growth" stage of the product life cycle. Moreover, with today's purchasing emphasis on supplier reduction, the current market for third-party logistics services may expand into the emerging market for single-source supply systems. Succinctly stated, the adoption of third-party logistics does not appear to be a passing fad in the USA.The authors would like to thank Caterpillar Logistics Services for their support in this research.
The natural interspecies Saccharomyces cerevisiae × Saccharomyces eubayanus hybrid yeast is responsible for global lager beer production and is one of the most important industrial microorganisms. Its success in the lager brewing environment is due to a combination of traits not commonly found in pure yeast species, principally low-temperature tolerance, and maltotriose utilization. Parental transgression is typical of hybrid organisms and has been exploited previously for, e.g., the production of wine yeast with beneficial properties. The parental strain S. eubayanus has only been discovered recently and newly created lager yeast strains have not yet been applied industrially. A number of reports attest to the feasibility of this approach and artificially created hybrids are likely to have a significant impact on the future of lager brewing. De novo S. cerevisiae × S. eubayanus hybrids outperform their parent strains in a number of respects, including, but not restricted to, fermentation rate, sugar utilization, stress tolerance, and aroma formation. Hybrid genome function and stability, as well as different techniques for generating hybrids and their relative merits are discussed. Hybridization not only offers the possibility of generating novel non-GM brewing yeast strains with unique properties, but is expected to aid in unraveling the complex evolutionary history of industrial lager yeast.
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