Microbial Resources and Systematics
Online ISSN : 2759-2006
Print ISSN : 1342-4041
Volume 33, Issue 2
Displaying 1-18 of 18 articles from this issue
  • Makoto M. Watanabe
    2017 Volume 33 Issue 2 Pages 47-54
    Published: 2017
    Released on J-STAGE: November 22, 2024
    JOURNAL FREE ACCESS

    Microalgae are among the most sustainable feedstocks for biofuels because they produce more oil than land plants and their production does not compete with existing food production. Moreover, seawater is readily available for use by marine algal species. Worldwide, research and demonstration programs are being performed to develop the technology needed to expand algal biomass production from a craft to a major industrial process. Native algal community polycultures are efficient at nutrient utilization owing to niche complementation, and they therefore offer higher biomass productivity than monocultures. Whole-algal hydrothermal liquefaction (HTL) is ideal for complex communities of algae, as it avoids the potential need to separate algal strains and species. The combination of polyculture and HTL technologies is a key R & D issue for cost-effective production of algae fuels.

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  • Misa Otoguro, Kotaro Maeda, Munekazu Kishimoto, Hideki Yamamura, Katsu ...
    2017 Volume 33 Issue 2 Pages 55-62
    Published: 2017
    Released on J-STAGE: November 22, 2024
    JOURNAL FREE ACCESS

    Enrichment or dilution methods are generally used for isolating lactic acid bacteria (LAB) from natural samples. However, these methods depend on the microbe's predominant characteristics or growth rate. Here, we developed a new method for isolating minor LAB by co-culture with yeast strains. We then used this method to isolate rare and indigenous species in the traditional fermented foods of Myanmar, thus enabling us to determine the taxonomic diversity of LAB there. To analyze the effects of co-culture we tested a combination of 18 species and 2 subspecies of LAB and 6 species of yeast. Interestingly, some specific combinations either accelerated or suppressed LAB growth. Eight fish or prawn products fermented with rice (ngachin and pazun-chin) were then obtained from the Ayeyawady market in Myanmar for testing. By using co-culture and dilution methods we isolated 52 LAB from these products. Co-culture with yeast resulted consistently in LAB isolation from all samples. The LAB were assigned to 3 genera and 15 species; the genus Lactobacillus accounted for 85% (44 strains) of the bacteria in these products. 16S rDNA analysis showed that one new species candidate was isolated by the dilution method, whereas 2 new species candidates were isolated by the co-culture method. Lactobacillus futsaii and Lactobacillus plajomi, isolated recently from Taiwanese fermented mustard products and from Thai fermented food, respectively, were also detected by the dilution method. However, the genus Weissella was isolated only by co-culture with Saccharomyces cerevisiae. Thus, co-culture enabled the isolation of rare LAB that are otherwise difficult to isolate by using the normal dilution method. Our results suggest that the development of new methodologies for isolating LAB is highly important for expanding our understanding of their ecology, taxonomy, and distribution.

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