Engineering Synthetic Microbial Communities through a Selective Biofilm Cultivation Device for the Production of Fermented Beverages

Abstract

Production of Cambodian rice wine involves complex microbial consortia. Indeed, previous studies focused on traditional microbial starters used for this product revealed that three microbial strains with complementary metabolic activities are required for an effective fermentation, i.e., filamentous fungi (Rhizopus oryzae), yeast (Saccharomyces cerevisiae), and lactic acid bacteria (Lactobacillus plantarum). Modulating the ratio between these three key players led to significant differences, not only in terms of ethanol and organic acid production, but also on the profile of volatile compounds, in comparison with natural communities. However, we observed that using an equal ratio of spores/cells of the three microbial strains during inoculation led to flavor profile and ethanol yield close to that obtained through the use of natural communities. Compartmentalization of metabolic tasks through the use of a biofilm cultivation device allows further improvement of the whole fermentation process, notably by increasing the amount of key components of the aroma profile of the fermented beverage (i.e., mainly phenylethyl alcohol, isobutyl alcohol, isoamyl alcohol, and 2-methyl-butanol) and reducing the amount of off-flavor compounds. This study is a step forward in our understanding of interkingdom microbial interactions with strong application potential in food biotechnology.

Microbial Community Dynamics and Metabolome Changes During Spontaneous Fermentation of Northeast Sauerkraut From Different Households

“…Compared with the other sauerkraut samples, the content of total esters in #2 sauerkraut samples was significantly higher. Ethyl lactate and ethyl isovalerate were detected only in #3 sauerkraut, which were recognized as being fruity and floral aroma with lower detection threshold (Ly et al, 2019). Similarly, lactones also have fruity and floral odor notes, which contribute significantly to the flavor characteristic of fermented foods (Lee et al, 2018).…”

Multispecies biofilms in fermentation: Biofilm formation, microbial interactions, and communication

“…Biofilm reactors are easy to manipulate in continuous processes and greatly capitalize on cell immobilization of biofilms with high cell density, high stress tolerance, and high productivity (Todhanakasem, 2017). In the production of fermented beverages, Rhizopus oryzae , S. cerevisiae , and L. plantarum , with complementary metabolic activities, were key microorganisms in the fermentation of Cambodian rice wine (Ly et al., 2019). Mixed‐species biofilm formation on the biofilm cultivation device depended on the initial colonization of R. oryzae , and a growth‐promoted interaction between S. cerevisiae and L. plantarum was found.…”

Biofilm Mode of Cultivation Leads to an Improvement of the Entomotoxic Patterns of Two Aspergillus Species

“…This support was composed of two pieces of porous stainless steel 316 L (70 mm × 60 mm, Sulzer, Winterthur, Switzerland) that were arranged in opposition and attached ( Figure 1). The same system has been previously used for growing Trichoderma harzianum for the production of hydrophobin [20] and for the growth of Rhizopus oryzae in interaction with yeasts and lactic acid bacteria [21]. The cultures were performed at 30 • C and 125 rpm for five days.…”