Bioaerosols in the Food and Beverage Industry

Bioaerosol monitoring is a rapidly emerging area of industrial hygiene. Microbial roles in atmospheric processes are thought to be species specific and potentially depend on cell viability. Accumulating evidence suggests that exposure to bioaerosols may cause adverse health effects, including disease. Studies of bioaerosols have primarily focused on chemical composition and biological composition, and the negative effects thereof on ecosystems and human health have largely gone unnoticed. This gap can be attributed to international standards on acceptable maximum bioaerosol loads not being uniform and the lack of uniform standardized methods for collection and analysis of bacterial and fungal bioaerosols. In this chapter, bioaerosol composition, relevance of bioaerosols to the food processing facility, sampling and detection approaches, and complications were discussed

Reconstructing functional networks in the human intestinal tract using synthetic microbiomes : Systems Biology • Nanobiotechnology

The human intestinal tract harbors one of the most densely populated and open microbial ecosystems. The application of multi-omics approaches has provided insight into a wide array of complex interactions between the various groups of mainly anaerobic colonic microbes as well as the host-microbe dialogue. Integration of multi-omits techniques in cultivation based experiments that vary in complexity from monocultures to synthetic microbial communities identified key metabolic players in the trophic interactions as well as their ecological dynamics. A synergy between these approaches will be of utmost importance to reconstruct the functional interaction networks at the ecosystem level within the human intestinal microbiome. The improved understanding of microbiome functioning at ecosystem level will further aid in developing better predictive models and design of effective microbiome modulation strategies for health benefits.Peer reviewe

vanI : a novel D-Ala-D-Lac vancomycin resistance gene cluster found in Desulfitobacterium hafniense

Peer reviewe

Flux, Impact, and Fate of Halogenated Xenobiotic Compounds in the Gut

Humans and their associated microbiomes are exposed to numerous xenobiotics through drugs, dietary components, personal care products as well as environmental chemicals. Most of the reciprocal interactions between the microbiota and xenobiotics, such as halogenated compounds, occur within the human gut harboring diverse and dense microbial communities. Here, we provide an overview of the flux of halogenated compounds in the environment, and diverse exposure routes of human microbiota to these compounds. Subsequently, we review the impact of halogenated compounds in perturbing the structure and function of gut microbiota and host cells. In turn, cultivation-dependent and metagenomic surveys of dehalogenating genes revealed the potential of the gut microbiota to chemically alter halogenated xenobiotics and impact their fate. Finally, we provide an outlook for future research to draw attention and attract interest to study the bidirectional impact of halogenated and other xenobiotic compounds and the gut microbiota.Peer reviewe

Intestinal microbiome landscaping : insight in community assemblage and implications for microbial modulation strategies

High individuality, large complexity and limited understanding of the mechanisms underlying human intestinal microbiome function remain the major challenges for designing beneficial modulation strategies. Exemplified by the analysis of intestinal bacteria in a thousand Western adults, we discuss key concepts of the human intestinal microbiome landscape, i.e. the compositional and functional 'core', the presence of community types and the existence of alternative stable states. Genomic investigation of core taxa revealed functional redundancy, which is expected to stabilize the ecosystem, as well as taxa with specialized functions that have the potential to shape the microbiome landscape. The contrast between Prevotella-and Bacteroides-dominated systems has been well described. However, less known is the effect of not so abundant bacteria, for example, Dialister spp. that have been proposed to exhibit distinct bistable dynamics. Studies employing time-series analysis have highlighted the dynamical variation in the microbiome landscape with and without the effect of defined perturbations, such as the use of antibiotics or dietary changes. We incorporate ecosystem-level observations of the human intestinal microbiota and its keystone species to suggest avenues for designing microbiome modulation strategies to improve host health.Peer reviewe

Culture-Dependent Diversity Profiling of Spoilage Yeasts Species by PCR-RFLP Comparative Analysis

Published ArticleSpoilage caused by yeasts is a constant, widespread problem in the beverage industry that can result in major economic losses. Fruit juices provide an environment that allows the proliferation of yeast. Some factories in South Africa are not equipped with laboratory facilities to identify spoilage yeasts and outsourcing becomes a prolonged process which obstructs corrective action planning. This study aimed to establish yeast diversity and apply a rapid method for preliminary identification of spoilage yeasts associated with a small-scale fruit juice bottling factory. Yeast population in the factory was determined by isolation from the production environment, process equipment and spoiled products. PCR-RFLP analysis targeting the 5.8S-ITS region and D1/D2 sequencing was used for identification. A total of 207 yeasts belonging to 10 different genera (Candida, Lodderomyces, Wickerhamomyces, Yarrowia, Zygosaccharomyces, Zygoascus, Cryptococcus, Filobasidium, Rhodotorula/Cystobasidium and Trichosporon) were isolated and identified from the production environment and processing equipment. Candida intermedia, C. parapsilosis and Lodderomyces elongisporus were widely distributed in the factory. Zygosaccharomyces bailii, Z. bisporus, Zygoascus hellenicus and Saccharomyces cerevisiae were isolated from the spoiled products. The data provided a yeast control panel that was used successfully to identify unknown yeasts in spoiled products from this factory using polymerase chain reaction-restriction length polymorphism (PCR-RFLP) comparative analysis

Unravelling lactate-acetate and sugar conversion into butyrate by intestinal Anaerobutyricum and Anaerostipes species by comparative proteogenomics

Thed- andl-forms of lactate are important fermentation metabolites produced by intestinal bacteria but are found to negatively affect mucosal barrier function and human health. Both enantiomers of lactate can be converted with acetate into the presumed beneficial butyrate by a phylogenetically related group of anaerobes, includingAnaerobutyricumandAnaerostipesspp. This is a low energy yielding process with a partially unknown pathway inAnaerobutyricumandAnaerostipesspp. and hence, we sought to address this via a comparative genomics, proteomics and physiology approach. We compared growth ofAnaerobutyricum soehngeniion lactate with that on sucrose and sorbitol. Comparative proteomics revealed complete pathway of butyrate formation from sucrose, sorbitol and lactate. Notably, a gene cluster,lctABCDEFwas abundantly expressed when grown on lactate. This gene cluster encodes a lactate dehydrogenase (lctD), electron transport proteins A and B (lctCB), nickel-dependent racemase (lctE), lactate permease (lctF) and short-chain acyl-CoA dehydrogenase (lctG). Investigation of available genomes of intestinal bacteria revealed this new gene cluster to be highly conserved in onlyAnaerobutyricumandAnaerostipesspp. Present study demonstrates thatA. soehngeniiand several relatedAnaerobutyricumandAnaerostipesspp. are highly adapted for a lifestyle involving lactate plus acetate utilization in the human intestinal tract.Peer reviewe