Bacterial consortia constructed for the decomposition ofAgavebiomass

Abstract

Research has shown that a greater variety of enzymes, as well as variety of microorganisms producing enzymes, can have an overall synergistic effect on the decomposition of lignocellulosic biomass for the production of value-added bio-products. Here, 8 cellulase-degrading bacterial isolates were selected to develop co-, tri-, and tetra-cultures for the decomposition of lignocellulosic biomass. Glucose and xylose equivalents released from imitation biomass media containing 0.5% (w/v) beechwood xylan and 0.5% (w/v) Avicel was measured using di-nitrosalicylic acid for all consortia, along with cell growth and survival. Thereafter, 6 co- and 2 tri-cultures with greatest decomposition were examined for ability to degrade Agave americana fiber. Interestingly, when strains were paired up in co-culture, four pairs: G+5, G+A, C+A1, and G+A1 produced high reducing sugars in 24 h: 6 µM, 8 µM, 8 µM, and finally, 6 µM, respectively. From 4 co-cultures with highest reducing sugar equivalents, tri- and tetra-cultures were produced. The bacterial consortia which had the highest reducing sugars detected were 2 tri-cultures: G + A1 + A4 and G + A1 + 5, displaying levels as high as 9 µM and 5 µM in day 1, respectively. All co- and tri-cultures maintained high cell survival for 14 days with 0.5 g ground Agave. Upon evaluating Agave dry weight after treatment, it was evident that almost half the biomass could be decomposed in 14 days. Scanning electron microscopy of treated Agave supported decomposition when compared with the control. These bacterial consortia have potential for further study of value-added by-product production during metabolism of lignocellulosic biomasses.

A Novel Triculture System (CC3) for Simultaneous Enzyme Production and Hydrolysis of Common Grasses through Submerged Fermentation

“…Consortium of microbes especially that of bacterial strains capable of surviving together and synergistically produce hydrolytic enzymes have gained immense interest, given their ability to perform more complex tasks and more readily adapt to changes in the environment than mono-culture (Maki et al, 2014 ). In the present study, an effective system having bioconversion capabilities (for the selected biomass) by producing both holocellulose (cellulose + hemicellulose) degrading enzymes was performed successfully.…”

“…In the present study, an effective system having bioconversion capabilities (for the selected biomass) by producing both holocellulose (cellulose + hemicellulose) degrading enzymes was performed successfully. One major advantage of microbial consortium is the enzymes secreted by various microbes could compensate the absence of another enzyme required for degradation (Maki et al, 2014 ). This was clearly indicated by the increase in the enzyme activities of the tested CC3 system along with the emergence of all four enzymes whose synergy was absent in mono (CC1) and coculture (CC2) systems.…”

“…The plates were incubated for 24 h at 28°C before being counted. All experiments were performed in triplicate and the cell densities were expressed in log (CFU/ml) (Maki et al, 2014 ).…”

Better together: engineering and application of microbial symbioses

“…[73] Similar benefits from communities have been seen in efforts to use cellulosic feedstocks for energy, which is a costly metabolically but is effectively achieved in consortia. [74,75] Cocultures have been engineered to take the system one step further by going from cellulose to product. [76][77][78] Minty and colleagues accomplished this by pairing a fungus that breaks down cellulose with engineered E. coli that make isobutanol (Figure 4b).…”

Enhanced Endoglucanase Production by Bacillus aerius on Mixed Lignocellulosic Substrates

“…The gravimetric method evaluates the cellulolytic ability of bacteria on different lignocellulosic substrates (Gupta et al 2012;Maki et al 2014).…”