Microencapsulated and subsequently freeze-dried cells showed acceptable storage stability and enhanced survival during in vitro upper gastrointestinal tract passage.
SARS-CoV-2 is a very transmissible and pathogenic coronavirus which detected in Malaysia in January 2020. Nevertheless, the sample from Malaysia is still under-sequenced. Hence lacking clarity of the circulating strain in Malaysia leads to a deadlock in understanding the virus infectivity. This study aimed to investigate the genome identity of circulating COVID-19 strains in Pahang and understand disease epidemiology during the pandemic. This study leveraged high-throughput sequencing analysis for the whole genome sequencing and implemented bioinformatic technique for the analysis. Here we reported that the virus with D614G mutation in Spike protein circulates in a few Malaysia states before the Sivagangga cluster announced in Kedah in July 2020. This mutated virus includes our virus sample isolated in April 2020 from an asymptomatic patient in Pahang. Based on the phylogenetic analysis, we discovered the origin of our sample Pahang/IIUM91 was not related to Sivagangga cluster. Here, we have generated 3D structure model of Pahang/IIUM91 Spike protein. D614G mutation in Pahang/IIUM91 Spike protein increases viral stability and flexibility, hence render higher infectivity. Collectively, our results suggest for the establishment of a complete SARS-CoV-2 genome database in Malaysia. Hence, more research should be established to learn the behaviour of this virus.
To exert a beneficial effect on the host, adequate doses of probiotics must be administered and maintaining their viability until consumption is thus essential. Dehydrated probiotics exhibit enhanced long-term viability and can be incorporated into low-moisture food matrices, which also possess high stability at refrigeration and ambient temperature. However, several factors associated with the desiccation process, the physicochemical properties of the matrix and the storage conditions can affect probiotic survival. In the near future, an increased demand for probiotics based on functionally dominant members of the gut microbiome (‘next-generation probiotics’, NGP) is expected. NGPs are very sensitive to oxygen and efficient encapsulation protocols are needed. Strategies to improve the viability of traditional probiotics and particularly of NGPs involve the selection of a suitable carrier as well as proper desiccation and protection techniques. Dehydrated probiotic microcapsules may constitute an alternative to improve the microbial viability during not only storage but also upper gastrointestinal tract passage. Here we review the main dehydration techniques that are applied in the industry as well as the potential stresses associated with the desiccation process and storage. Finally, low- or intermediate-moisture food matrices suitable as carriers of traditional as well as NGPs will be discussed.
The viability of probiotics is affected by several factors during manufacturing, storage and gastrointestinal tract passage. Protecting the probiotics from harmful conditions is particularly critical for oxygen sensitive species like Akkermansia muciniphila, a bacterium which recently has been proposed as a next-generation probiotic candidate. Previously, we have developed a protocol for microencapsulating A. muciniphila in a xanthan/gellan gum matrix. Here, we report the enhanced survival during storage and in vitro gastric passage of microencapsulated A. muciniphila embedded in dark chocolate. Lactobacillus casei, as a representative species of traditional probiotics, was included in order to compare its behavior with that of A. muciniphila. For A. muciniphila we observed a 0.63 and 0.87 log CFU g−1 reduction during 60 days storage at 4°C or 15°C, respectively. The viability of L. casei remained stable during the same period. During simulated gastric transit (pH 3), microencapsulated A. muciniphila embedded in chocolate showed 1.80 log CFU mL−1 better survival than naked cells, while for L. casei survival was improved with 0.8 log CFU mL−1. In a hedonic sensory test, dark chocolate containing microcapsules were not significantly different from two commercially available chocolates. The developed protocol constitutes a promising approach for A. muciniphila dosage.
As a function of the global necessity to reduce or replace the use of chemical fertilisers and pesticides, due to their toxicity, the formulation of microbial inoculants has been suggested as an environmentally friendly alternative for maintaining crop production at economically sustainable levels. In this connection, the microencapsulation of beneficial soil‐borne microorganisms is conceived as a strategy to improve the inoculant's efficiency, in terms of viability and functionality. In this article, we describe the most widely applied microencapsulation techniques, including the mechanisms and wall materials involved, as well as the advantages and shortcomings of using different encapsulation technologies. Moreover, the desiccation technologies used as a tool to extend the shelf‐life of immobilised microbes are also explained. Finally, the outcomes of various, relatively recent studies regarding the encapsulation of plant growth‐promoting microorganisms and biocontrol agents, including bacteriophages, are discussed. This article may contribute to the design of microbial inoculant delivery strategies, aiming to increase crop production and to reduce the utilisation of chemical fertilisers and pesticides.
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