Consolidated Bioprocessing of Hemicellulose-Enriched Lignocellulose to Succinic Acid through a Microbial Cocultivation System

Abstract

Consolidated bioprocessing (CBP) has been considered as a cost-effective strategy for the efficient bioconversion of lignocellulosic biomass into valuable chemicals. Microbial consortium can complete the complex CBP process through the cooperation within different microorganisms. In this study, a proof-of-concept CBP microbial consortium was designed, which is composed of a hemicellulase-producing bacterium Thermoanaerobacterium thermosaccharolyticum M5 and a succinic acid production specialist Actinobacillus succinogenes 130Z. The continuous conversion of xylan to xylose by T. thermosaccharolyticum could maintain a high hydrolyzing rate, which would facilitate the following succinic acid production by A. succinogenes 130Z. After the process optimization including inoculation time, pH, and so forth, 32.50 g/L of succinic acid with a yield of 0.39 g/g was obtained from xylan through CBP, representing the highest succinic acid production directly from hemicellulose materials. In addition, 12.51 g/L of succinic acid was directly produced from 80 g/L of untreated corn cob. These results demonstrated that the proof-ofconcept application of this CBP-based microbial cocultivation system could be readily adopted for bioconversion of lignocellulosic biomass into other valuable biochemicals.

Challenges and Future Perspectives of Promising Biotechnologies for Lignocellulosic Biorefinery

“…These two strains can generate well supplementary interaction, making fermentation process more efficiently, and 7.61 g/L of butanol was directly produced from corncob. Similarly, a microbial co-culturing system containing A. succinogenes 130Z and T. thermosaccharolyticum M5 also achieved succinic acid production from lignocellulosic materials [105]. After single-element and response surface optimization, the optimal production of succinic acid was 32.50 g/L and 12.5g/L from 84 g/L xylan and 80 g/L corncob, respectively.…”

Comprehensive evaluation for the one-pot biosynthesis of butyl acetate by using microbial mono- and co-cultures

“…The P1 fermentation medium contains 0.75 g/L of KH 2 PO 4 , 0.75 g/L of K 2 HPO 4 , 4.585 g/L of 2-[[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino]ethanesulfonic acid, and 5 g/L of yeast extract. 1 mL of Na 2 SeO 3 –Na 2 WO 4 solution [ 35 ], 1 mL of trace element solution [ 20 ], 10 mL of salt solution [ 35 ], and 10 mg of resazurin (oxygen indicator) were added into 1 L medium, respectively. In addition, 0.024 g/L of l (+)-cysteine was added as reductants under N 2 .…”

“…The relationship between dependent and independent variables is explained through the following second order polynomial equation: where Y is predicted response (butyl acetate concentration); X 1 , X 2 , and X 3 are independent variables (pH, acetic acid supplemental concentration and acetic acid addition time); α 0 is offset term; α 1 , α 2 , and α 3 are linear effects; α 12 , α 13 , and α 23 are squared effects; and α 11 , α 22 , and α 33 are interaction terms. Analysis of variance (ANOVA) was used to perform statistical analysis of the model [ 35 ]. For microbial monoculture of A. succinogenes 130z (Δ pflA ), the influence of several single factors, such as extracting agent, lipase supplemental level, speed, and butanol concentration, on the butyl acetate production was explored.…”

Valorisation of xylose to renewable fuels and chemicals, an essential step in augmenting the commercial viability of lignocellulosic biorefineries

“…The consortium with the consolidated bioprocessing approach was able to generate 32.5 g L −1 SA with a yield of 0.39 g g −1 . 139 …”