Fermentation of Dairy-Relevant Sugars by Saccharomyces, Kluyveromyces, and Brettanomyces: An Exploratory Study with Implications for the Utilization of Acid Whey, Part I

Acid whey from Greek-style yogurt (YAW) is an underutilized byproduct and a challenge for the dairy industry. One alternative is the fermentation of YAW by yeasts such as Saccharomyces, Brettanomyces, and Kluyveromyces spp., to produce new styles of fermented beverages. Previous research in our group suggested that the sugar profiles of the dairy coproducts impacted the fermentation profiles produced by B. claussenii. The present work aims to describe the fermentation of dairy sugars by S. cerevisiae, K. marxianus, and B. claussenii, under conditions comparable to those of YAW. For this purpose, four preparations of yeast nitrogen base, each containing 40 g/L of either lactose (LAC), glucose (GLU), galactose (GAL), or a 1:1 mixture of glucose and galactose (GLU:GAL), all at pH 4.20, were used as fermentation media. The fermentation was performed independently by each organism at 25 °C under anoxic conditions, while density, pH, cell count, ethanol, and organic acids were monitored. Non-linear modeling was used to characterize density curves, and Analysis of Variance and Tukey’s Honest Significant Difference tests were used to compare fermentation products. K. marxianus and S. cerevisiae displayed rapid sugar consumption with consistent ethanol yields in all media, as opposed to B. claussenii, which showed more variable results. The latter organism exhibited what appears to be a selective glucose fermentation in GLU:GAL, which will be explored in the future. These results provide a deeper understanding of dairy sugar utilization by relevant yeasts, allowing for future work to optimize fermentations to improve value-added beverage and ingredient production from YAW.

Download Full-text

D-Fructose Assimilation and Fermentation by Yeasts Belonging to Saccharomycetes: Rediscovery of Universal Phenotypes and Elucidation of Fructophilic Behaviors in Ambrosiozyma platypodis and Cyberlindnera americana

Microorganisms ◽

10.3390/microorganisms9040758 ◽

2021 ◽

Vol 9 (4) ◽

pp. 758

Author(s):

Rikiya Endoh ◽

Maiko Horiyama ◽

Moriya Ohkuma

Keyword(s):

Yeast Species ◽

Yeast Nitrogen Base ◽

Sugar Consumption ◽

Nitrogen Base ◽

Physiological Properties ◽

Standard Set ◽

Durham Tube ◽

Ascomycetous Yeasts ◽

Almost All ◽

Ubiquitous Presence

The purpose of this study was to investigate the ability of ascomycetous yeasts to assimilate/ferment d-fructose. This ability of the vast majority of yeasts has long been neglected since the standardization of the methodology around 1950, wherein fructose was excluded from the standard set of physiological properties for characterizing yeast species, despite the ubiquitous presence of fructose in the natural environment. In this study, we examined 388 strains of yeast, mainly belonging to the Saccharomycetes (Saccharomycotina, Ascomycota), to determine whether they can assimilate/ferment d-fructose. Conventional methods, using liquid medium containing yeast nitrogen base +0.5% (w/v) of d-fructose solution for assimilation and yeast extract-peptone +2% (w/v) fructose solution with an inverted Durham tube for fermentation, were used. All strains examined (n = 388, 100%) assimilated d-fructose, whereas 302 (77.8%) of them fermented d-fructose. In addition, almost all strains capable of fermenting d-glucose could also ferment d-fructose. These results strongly suggest that the ability to assimilate/ferment d-fructose is a universal phenotype among yeasts in the Saccharomycetes. Furthermore, the fructophilic behavior of Ambrosiozyma platypodis JCM 1843 and Cyberlindnera americana JCM 3592 was characterized by sugar consumption profiles during fermentation.

Download Full-text

INITIAL STEP OF SPECIALIZED CORPORA BUILDING: CLEANING PROCEDURES

NORDSCI Conference proceedings, Book 1 Volume 3 ◽

10.32008/nordsci2020/b1/v3/16 ◽

2020 ◽

Author(s):

Vera Yakubson ◽

Victor Zakharov

Keyword(s):

Text Processing ◽

Research Question ◽

Initial Step ◽

Main Research ◽

Academic Texts ◽

Linguistic Annotation ◽

Significant Difference ◽

Cleaning Procedures ◽

Unique Source ◽

Future Work

This paper deals with the specialized corpora building, specifically academic language corpus in the biotechnology field. Being a part of larger research devoted to creation and usage of specialized parallel corpus, this piece aims to analyze the initial step of corpus building. Our main research question was what procedures we need to implement to the texts before using them to develop the corpus. Analysis of previous research showed the significant quantity of papers devoted to corpora creation, including academic specialized corpora. Different sides of the process were analyzed in these researches, including the types of texts used, the principles of crawling, the recommended length of texts etc. As to the text processing for the needs of corpora creation, only the linguistic annotation issues were examined earlier. At the same time, the preliminary cleaning of texts before their usage in corpora may have significant influence on the corpus quality and its utility for the linguistic research. In this paper, we considered three small corpora derived from the same set of academic texts in the biotechnology field: “raw” corpus without any preliminary cleaning and two corpora with different level of cleaning. Using different Sketch Engine tools, we analyzed these corpora from the position of their future users, predominantly as sources for academic wordlists and specialized multi-word units. The conducted research showed very little difference between two cleaned corpora, meaning that only basic cleaning procedures such as removal of reference lists are can be useful in corpora design. At the same time, we found a significant difference between raw and cleaned corpora and argue that this difference can affect the quality of wordlists and multi-word terms extraction, therefore these cleaning procedures are meaningful. The main limitation of the study is that all texts were taken from the unique source, so the conclusions could be affected by this specific journal’s peculiarities. Therefore, the future work should be the verification of results on different text collections

Download Full-text

Women’s Economic Empowerment in Vietnam: Performance and Constraints of Female-Led Manufacturing SMEs

Journal of Risk and Financial Management ◽

10.3390/jrfm14060255 ◽

2021 ◽

Vol 14 (6) ◽

pp. 255

Author(s):

MinhTam Bui ◽

Trinh Q. Long

Keyword(s):

Labor Productivity ◽

Small And Medium Enterprises ◽

Manufacturing Sector ◽

Value Added ◽

Medium Size ◽

Formal Sector ◽

Firm Level ◽

Average Value ◽

Significant Difference ◽

Medium Enterprises

This paper identifies whether there was a performance difference among micro, small and medium enterprises (MSMEs) led by men and by women in Vietnam during the period 2005–2013 and aims to provide explanations for the differences, if any, in various performance indicators. The paper adopts a quantitative approach using a firm-level panel dataset in the manufacturing sector in 10 provinces/cities in Vietnam in five waves from 2005 to 2013. Fixed effect models are estimated to examine the influence of firm variables and demographic, human capital characteristics of owners/managers on firms’ value added, labor productivity and employment creation. We found that men led MSMEs did not outperform those led by women on average. Although the average value added was lower for female-led firms in the informal sector, the opposite was true in the formal sector where women tend to lead medium-size firms with higher value added and labor productivity. The performance disparity was more envisaged across levels of formality and less clear from a gender perspective. Moreover, while firms owned by businessmen seemed to create more jobs, firms owned by women had a higher share of female employees. No significant difference in business constraints faced by women and by men was found.

Download Full-text

Nanotubular Oxide Layer Formed on Helix Surfaces of Dental Screw Implants

Coatings ◽

10.3390/coatings11020115 ◽

2021 ◽

Vol 11 (2) ◽

pp. 115 ◽

Cited By ~ 1

Author(s):

Magdalena Jażdżewska ◽

Michał Bartmański

Keyword(s):

Oxide Layer ◽

Cross Sections ◽

Surface Coverage ◽

Artificial Saliva ◽

Corrosion Current ◽

Optical Microscope ◽

Significant Difference ◽

Helix Surfaces ◽

Future Work ◽

Oxidation Parameters

Surface modification is used to extend the life of implants. To increase the corrosion resistance and improve the biocompatibility of metal implant materials, oxidation of the Ti-13Nb-13Zr titanium alloy was used. The samples used for the research had the shape of a helix with a metric thread, with their geometry imitating a dental implant. The oxide layer was produced by a standard electrochemical method in an environment of 1M H3PO4 + 0.3% HF for 20 min, at a constant voltage of 30 V. The oxidized samples were analyzed with a scanning electron microscope. Nanotubular oxide layers with internal diameters of 30–80 nm were found. An analysis of the surface topography was performed using an optical microscope, and the Sa parameter was determined for the top of the helix and for the bottom, where a significant difference in value was observed. The presence of the modification layer, visible at the bottom of the helix, was confirmed by analyzing the sample cross-sections using computed tomography. Corrosion tests performed in the artificial saliva solution demonstrated higher corrosion current and less noble corrosion potential due to incomplete surface coverage and pitting. Necessary improved oxidation parameters will be applied in future work.

Download Full-text

Kinetics and Metabolism of Bifidobacterium adolescentis MB 239 Growing on Glucose, Galactose, Lactose, and Galactooligosaccharides

Applied and Environmental Microbiology ◽

10.1128/aem.02914-06 ◽

2007 ◽

Vol 73 (11) ◽

pp. 3637-3644 ◽

Cited By ~ 62

Author(s):

Alberto Amaretti ◽

Tatiana Bernardi ◽

Elena Tamburini ◽

Simona Zanoni ◽

Mariella Lomma ◽

...

Keyword(s):

Growth Rate ◽

Recursive Algorithm ◽

Carbon Fluxes ◽

Degree Of Polymerization ◽

Substrate Selectivity ◽

Carbon Distribution ◽

Bifidobacterium Adolescentis ◽

Fermentation Products ◽

Batch Cultures ◽

Ethanol Yields

ABSTRACT The kinetics and the metabolism of Bifidobacterium adolescentis MB 239 growing on galactooligosaccharides (GOS), lactose, galactose, and glucose were investigated. An unstructured unsegregated model for growth in batch cultures was developed, and kinetic parameters were calculated with a recursive algorithm. The growth rate and cellular yield were highest on galactose, followed by lactose and GOS, and were lowest on glucose. Lactate, acetate, and ethanol yields allowed the calculation of carbon fluxes toward fermentation products. Distributions between two- and three-carbon products were similar on all the carbohydrates (55 and 45%, respectively), but ethanol yields were different on glucose, GOS, lactose, and galactose, in decreasing order of production. Based on the stoichiometry of the fructose-6-phosphate shunt and on the carbon distribution among the products, the ATP yield was calculated. The highest yield was obtained on galactose, while the yields were 5, 8, and 25% lower on lactose, GOS, and glucose, respectively. Therefore, a correspondence among ethanol production, low ATP yields, and low biomass production was established, demonstrating that carbohydrate preferences may result from different distributions of carbon fluxes through the fermentative pathway. During the fermentation of a GOS mixture, substrate selectivity based on the degree of polymerization was exhibited, since lactose and the trisaccharide were the first to be consumed, while a delay was observed until longer oligosaccharides were utilized. Throughout the growth on both lactose and GOS, galactose accumulated in the cultural broth, suggesting that β(1-4) galactosides can be hydrolyzed before they are taken up.

Download Full-text

Differentiating aspects of product innovation processes in the food industry

British Food Journal ◽

10.1108/bfj-04-2013-0094 ◽

2014 ◽

Vol 116 (8) ◽

pp. 1346-1368 ◽

Cited By ~ 9

Author(s):

Rao Sanaullah Khan ◽

John Vincent Grigor ◽

Alan G. Win ◽

Mike Boland

Keyword(s):

New Zealand ◽

Manufacturing Industry ◽

Value Added ◽

Manufacturing Companies ◽

Food Manufacturing ◽

Content Type ◽

Significant Difference ◽

Group 2 ◽

Innovation Processes ◽

Group 1

Purpose – The purpose of this paper is to sketch a comparative account of NPD approaches between registered New Zealand food companies that are doing some sort of functional foods (FF) development (Group 1) and those that are not (Group 2); to generate a better understanding of differences and commonalities in their NPD approaches from resource-based view of competitive advantage. Design/methodology/approach – This paper opted an exploratory approach using a quantitative survey across food manufacturing companies in New Zealand. The primary foci of this empirical investigation were: orientation towards the NPD, innovation processes, collaborative NPD links and routes to commercialisation. Findings – The results (based on a 22 per cent response rate) show a significant difference (p<0.05) in the aims and mode of NPD between Groups 1 and 2. Further it was observed that food companies in Group 1 have significantly (p<0.05) more diverse external collaborations with broader aims to collaborate, in comparison with food companies in Group 2. Research limitations/implications – This study was conducted in New Zealand and thus generalisability of the findings may have to be interpreted carefully. Practical implications – The traditional NPD approach (independent and closed NPD), with loose intellectual property protection practices, dominates the food manufacturing industry in New Zealand. Research-oriented collaborations need to be strengthened in their scope and content to develop the innovative capabilities and capacities of small and medium enterprises (SME's) within future value-added food productions. Originality/value – This research provides the comparative narration of innovation process of food manufacturing companies with reference to FFs development.

Download Full-text

Social exclusion: re-examining its conceptual relevance to tackling inequality and social injustice

International Journal of Sociology and Social Policy ◽

10.1108/ijssp-05-2014-0040 ◽

2015 ◽

Vol 35 (9/10) ◽

pp. 600-617 ◽

Cited By ~ 7

Author(s):

Clive Sealey

Keyword(s):

Social Justice ◽

Social Policy ◽

Social Exclusion ◽

Design Methodology ◽

Value Added ◽

Social Injustice ◽

Critical Approach ◽

Content Type ◽

It Value ◽

Significant Difference

Purpose – The purpose of this paper is to rationalise the continued conceptual utility of social exclusion, and in so doing addresses the prevailing question of what to do with it. This is relevant from social exclusion’s declining relevance in contemporary UK social policy and academia, where its consideration as a concept to explain disadvantage is being usurped by other concepts, both old and new. Design/methodology/approach – The paper analyses criticisms of limitations of social exclusion which have typically centred on the operationalisation of the concept, but the author will argue that there are distinctive operationalisation and conceptual strengths within social exclusion which make it value-added as a concept to explain disadvantage. Specifically, there will be an analysis of both New Labour’s and the present Coalition government’s conceptualisation of the term in policy in relation to work. Findings – The analysis highlights the significant difference that a focus on processes rather than outcomes of social exclusion can make to our understanding of inequality and social injustice, and locates this difference within an argument that social exclusion’s true applied capabilities for social justice requires a shift to a conceptualisation built on the processes that cause it in the first place. Originality/value – The paper acts as a rejoinder to prevailing theoretical and political thinking of the limited and diminishing value of social exclusion for tackling disadvantage. In particular, the paper shows how social exclusion can be conceptualised to provide a critical approach to tackling inequality and social injustice, and in doing so foregrounds the truly applied capabilities of social exclusion for transforming social justice.

Download Full-text

Metabolic Engineering of Non-carotenoid-Producing Yeast Yarrowia lipolytica for the Biosynthesis of Zeaxanthin

Frontiers in Microbiology ◽

10.3389/fmicb.2021.699235 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yuxiao Xie ◽

Shulin Chen ◽

Xiaochao Xiong

Keyword(s):

Yarrowia Lipolytica ◽

Fold Increase ◽

Genetically Engineered ◽

Cell Factory ◽

Yeast Nitrogen Base ◽

Nitrogen Base ◽

Yeast Extract Peptone Dextrose ◽

Dry Cell Weight ◽

A Cell ◽

Β Carotene

Zeaxanthin is vital to human health; thus, its production has received much attention, and it is also an essential precursor for the biosynthesis of other critical carotenoids such as astaxanthin and crocetin. Yarrowia lipolytica is one of the most intensively studied non-conventional yeasts and has been genetically engineered as a cell factory to produce carotenoids such as lycopene and β-carotene. However, zeaxanthin production by Y. lipolytica has not been well investigated. To fill this gap, β-carotene biosynthesis pathway has been first constructed in this study by the expression of genes, including crtE, crtB, crtI, and carRP. Three crtZ genes encoding β-carotene hydroxylase from different organisms were individually introduced into β-carotene-producing Y. lipolytica to evaluate their performance for producing zeaxanthin. The expression of crtZ from the bacterium Pantoea ananatis (formerly Erwinia uredovora, Eu-crtZ) resulted in the highest zeaxanthin titer and content on the basis of dry cell weight (DCW). After verifying the function of Eu-crtZ for producing zeaxanthin, the high-copy-number integration into the ribosomal DNA of Y. lipolytica led to a 4.02-fold increase in the titer of zeaxanthin and a 721% increase in the content of zeaxanthin. The highest zeaxanthin titer achieved 21.98 ± 1.80 mg/L by the strain grown on a yeast extract peptone dextrose (YPD)–rich medium. In contrast, the highest content of DCW reached 3.20 ± 0.11 mg/g using a synthetic yeast nitrogen base (YNB) medium to culture the cells. Over 18.0 g/L of citric acid was detected in the supernatant of the YPD medium at the end of cultivation. Furthermore, the zeaxanthin-producing strains still accumulated a large amount of lycopene and β-carotene. The results demonstrated the potential of a cell factory for zeaxanthin biosynthesis and opened up an avenue to engineer this host for the overproduction of carotenoids.

Download Full-text

Correlation of Fluconazole MICs with Clinical Outcome in Cryptococcal Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.6.1544-1548.2000 ◽

2000 ◽

Vol 44 (6) ◽

pp. 1544-1548 ◽

Cited By ~ 114

Author(s):

A. I. Aller ◽

E. Martin-Mazuelos ◽

F. Lozano ◽

J. Gomez-Mateos ◽

L. Steele-Moore ◽

...

Keyword(s):

Clinical Outcome ◽

Maintenance Therapy ◽

National Committee ◽

Yeast Nitrogen Base ◽

Nitrogen Base ◽

Cryptococcal Infection ◽

Microdilution Method ◽

Cryptococcal Disease ◽

Fluconazole Therapy

ABSTRACT We have correlated the in vitro results of testing the susceptibility of Cryptococcus neoformans to fluconazole with the clinical outcome after fluconazole maintenance therapy in patients with AIDS-associated cryptococcal disease. A total of 28 isolates of C. neoformans from 25 patients (24 AIDS patients) were tested. The MICs were determined by the broth microdilution technique by following the modified guidelines described in National Committee for Clinical Standards (NCCLS) document M27-A, e.g., use of yeast nitrogen base medium and a final inoculum of 104 CFU/ml. The fluconazole MIC at which 50% of isolates are inhibited (MIC50) and MIC90, obtained spectrophotometrically after 48 h of incubation, were 4 and 16 μg/ml, respectively. Of the 25 patients studied, 4 died of active cryptococcal disease and 2 died of other causes. Therapeutic failure was observed in five patients who were infected with isolates for which fluconazole MICs were ≥16 μg/ml. Four of these patients had previously had oropharyngeal candidiasis (OPC); three had previously had episodes of cryptococcal infection, and all five treatment failure patients had high cryptococcal antigen titers in either serum or cerebrospinal fluid (titers, >1:4,000). Although 14 of the 18 patients who responded to fluconazole therapy had previously had OPC infections, they each had only a single episode of cryptococcal infection. It appears that the clinical outcome after fluconazole maintenance therapy may be better when the infecting C. neoformans strain is inhibited by lower concentrations of fluconazole for eradication (MICs, <16 μg/ml) than when the patients are infected with strains that require higher fluconazole concentrations (MICs, ≥16 μg/ml). These findings also suggest that the MICs determined by the modified NCCLS microdilution method can be potential predictors of the clinical response to fluconazole therapy and may aid in the identification of patients who will not respond to fluconazole therapy.

Download Full-text

Cell Surface Engineering of a β-Galactosidase for Galactooligosaccharide Synthesis

Applied and Environmental Microbiology ◽

10.1128/aem.00326-09 ◽

2009 ◽

Vol 75 (18) ◽

pp. 5938-5942 ◽

Cited By ~ 15

Author(s):

Yumei Li ◽

Lili Lu ◽

Hongmei Wang ◽

Xiaodong Xu ◽

Min Xiao

Keyword(s):

Cell Surface ◽

Surface Engineering ◽

Yeast Cells ◽

Penicillium Expansum ◽

Yeast Nitrogen Base ◽

Gene Encoding ◽

Nitrogen Base ◽

Reading Frame ◽

Acid Protein ◽

Casamino Acids

ABSTRACT A novel gene encoding transglycosylating β-galactosidase (BGase) was cloned from Penicillium expansum F3. The sequence contained a 3,036-bp open reading frame encoding a 1,011-amino-acid protein. This gene was subsequently expressed on the cell surface of Saccharomyces cerevisiae EBY-100 by galactose induction. The BGase-anchored yeast could directly utilize lactose to produce galactooligosaccharide (GOS), as well as the by-products glucose and a small quantity of galactose. The glucose was consumed by the yeast, and the galactose was used for BGase expression, thus greatly facilitating GOS synthesis. The GOS yield reached 43.64% when the recombinant yeast was cultivated in yeast nitrogen base-Casamino Acids medium containing 100 g/liter initial lactose at 25°C for 5 days. The yeast cells were harvested and recycled for the next batch of GOS synthesis. During sequential operations, both oligosaccharide synthesis and BGase expression were maintained at high levels with GOS yields of over 40%, and approximately 8 U/ml of BGase was detected in each batch.

Download Full-text