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Background: Utilization of commensal bacteria for delivery of medicinal proteins, such as vaccine antigens, is an emerging strategy. Here, we describe two novel food-grade strains of lactic acid bacteria, Lactiplantibacillus pentosus KW1 and KW2, as well as newly developed tools for using this relatively unexplored but promising bacterial species for production and surface-display of heterologous proteins. Results: Whole genome sequencing was performed to investigate genomic features of both strains and to identify native proteins enabling surface display of heterologous proteins. Basic characterization of the strains revealed the optimum growth temperatures for both strains to be 35–37 °C, with peak heterologous protein production at 33 °C (KW1) and 37 °C (KW2). Negative staining revealed that only KW1 produces closely bound exopolysaccharides. Production of heterologous proteins with the inducible pSIP-expression system enabled high expression in both strains. Exposure to KW1 and KW2 skewed macrophages toward the antigen presenting state, indicating potential adjuvant properties. To develop these strains as delivery vehicles, expression of the mycobacterial H56 antigen was fused to four different strain-specific surface-anchoring sequences. Conclusion: All experiments that enabled comparison of heterologous protein production revealed KW1 to be the better recombinant protein production host. Use of the pSIP expression system enabled successful construction of L. pentosus strains for production and surface display of an antigen, underpinning the potential of these strains as novel delivery vehicles. [ABSTRACT FROM AUTHOR]

Abstract The bulk terrestrial biomass resource in a future bio-economy will be lignocellulosic biomass, which is recalcitrant and challenging to process. Enzymatic conversion of polysaccharides in the lignocellulosic biomass will be a key technology in future biorefineries and this technology is currently the subject of intensive research. We describe recent developments in enzyme technology for conversion of cellulose, the most abundant, homogeneous and recalcitrant polysaccharide in lignocellulosic biomass. In particular, we focus on a recently discovered new type of enzymes currently classified as CBM33 and GH61 that catalyze oxidative cleavage of polysaccharides. These enzymes promote the efficiency of classical hydrolytic enzymes (cellulases) by acting on the surfaces of the insoluble substrate, where they introduce chain breaks in the polysaccharide chains, without the need of first “extracting” these chains from their crystalline matrix.

Abstract Background Little is known about the potential of Brachypodium distachyon as a model for low temperature stress responses in Pooideae. The ice recrystallization inhibition protein (IRIP) genes, fructosyltransferase (FST) genes, and many C-repeat binding factor (CBF) genes are Pooideae specific and important in low temperature responses. Here we used comparative analyses to study conservation and evolution of these gene families in B. distachyon to better understand its potential as a model species for agriculturally important temperate grasses. Results Brachypodium distachyon contains cold responsive IRIP genes which have evolved through Brachypodium specific gene family expansions. A large cold responsive CBF3 subfamily was identified in B. distachyon, while CBF4 homologs are absent from the genome. No B. distachyon FST gene homologs encode typical core Pooideae FST-motifs and low temperature induced fructan accumulation was dramatically different in B. distachyon compared to core Pooideae species. Conclusions We conclude that B. distachyon can serve as an interesting model for specific molecular mechanisms involved in low temperature responses in core Pooideae species. However, the evolutionary history of key genes involved in low temperature responses has been different in Brachypodium and core Pooideae species. These differences limit the use of B. distachyon as a model for holistic studies relevant for agricultural core Pooideae species.