Differentiation and secondary metabolism are correlated processes in fungi that respond to light. In
Aspergillus nidulans
, light inhibits sexual reproduction as well as secondary metabolism. We identified
the heterotrimeric
velvet
complex VelB/VeA/LaeA connecting light-responding developmental
regulation and control of secondary metabolism. VeA, which is primarily expressed in the dark,
physically interacts with VelB, which is expressed during sexual development. VeA bridges VelB to the
nuclear master regulator of secondary metabolism, LaeA. Deletion of either
velB
or
veA
results in
defects in both sexual fruiting-body formation and the production of secondary metabolites.

VelB/VeA/LaeA Complex CoordinatesLight Signal with Fungal Developmentand Secondary Metabolism

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C9NP00011A

Synergy and antagonism in natural product extracts: when 1 + 1 does not equal 2.

Plant expansins: diversity and interactions with plant cell walls

Lignocellulosic biomass has been considered as an important and sustainable source of renewable energy. Cellulose constitutes the major component of the lignocellulosic biomass and also offers maximum recalcitrance towards its fullest utilization. The enzymatic breakdown of cellulose is achieved through cellulases. Diverse forms of microbes including fungi, bacteria, actinomycetes and yeast are known to produce cellulases that have found extensive application in various industries. Due to the current global political unrest over oil prices and the threat of global warming following combustion of fossil fuels, the paradigm of research is now focused on biofuel production from plant biomass. Conventional approaches have not been economically feasible for meeting the demands of the industry. This review provides an update regarding the status of present microbial cellulase production technologies and research with special reference to solid state fermentation and different molecular techniques such as mutagenesis, metabolic engineering and heterologous gene expression of cellulases from different microbial domains with improved catalytic and stability properties. Metagenomic and genomic studies for mining of novel cellulase genes in addition to screening of culturable strains using conventional methods have been advanced. In addition the bottlenecks associated with cellulase production and how the future research needs to be directed to provide a comprehensive technology for the production of cellulases with novel traits for application at an industrial level without economic constraints are discussed.

Revisiting cellulase production and redefining current strategies based on major challenges.

Many biological or chemical agents when combined interact with each other and produce a synergistic response that cannot be predicted based on the single agent responses alone. However, depending on the postulated null hypothesis of non-interaction, one may end up in different interpretations of synergy. Two popular reference models for null hypothesis include the Bliss independence model and the Loewe additivity model, each of which is formulated from different perspectives. During the last century, there has been an intensive debate on the suitability of these synergy models, both of which are theoretically justified and also in practice supported by different schools of scientists. More than 20 years ago, there was a community effort to make a consensus on the terminology one should use when claiming synergy. The agreement was formulated at a conference held in Saariselka, Finland in 1992, stating that one should use the terms Bliss synergy or Loewe synergy to avoid ambiguity in the underlying models. We review the theoretical relationships between these models and argue that one should combine the advantages of both models to provide a more consistent definition of synergy and antagonism.

/pdf/what-is-synergy-the-saariselka-agreement-revisited-580nacsm4h.pdf

What is synergy? The Saariselkä agreement revisited.

https://www.tpbin.com/Uploads/Subjects/c5c3a05a-3809-4cfe-a757-b530c8a3de1a.pdf

Optimisation of synergistic biomass-degrading enzyme systems for efficient rice straw hydrolysis using an experimental mixture design

Binding characteristics and synergistic effects of bacterial expansins on cellulosic and hemicellulosic substrates.

Identification of novel bacterial expansins and their synergistic actions on cellulose degradation.

Lignocellulosic biomass serves as a renewable feedstock for production of biofuels and value-added biochemicals, and biorefinery of lignocellulosic feedstocks contributes greatly to the sustainable development of economy. However, release of fermentable sugars from lignocellulose is suffering from the high cost and low efficiency of lignocellulolytic enzymes. Filamentous fungi, especially Trichoderma reesei, are considered as the most efficient producers of lignocellulose-degrading enzymes, and improvement of enzyme production efficiency and optimization of enzyme composition are of great significance for biorefinery of lignocellulosic biomass. This review introduces the effects of environmental conditions, such as carbon and nitrogen sources, light and pH, on cellulase production from filamentous fungi. In addition, the recent progress on the novel regulatory network and the strategies for efficient cellulase induction and production in filamentous fungi are discussed. Optimization of cellulase ingredients and the effects of accessory enzymes on lignocellulose hydrolysis are also summarized. Efficient production of an optimized cocktail of lignocellulolytic enzymes with improved hydrolysis efficacy will greatly contribute to biofuels production from lignocellulosic biomass.

Benjarat Bunterngsook

Papers

Optimisation of synergistic biomass-degrading enzyme systems for efficient rice straw hydrolysis using an experimental mixture design

Binding characteristics and synergistic effects of bacterial expansins on cellulosic and hemicellulosic substrates.

Identification of novel bacterial expansins and their synergistic actions on cellulose degradation.

Regulation and production of lignocellulolytic enzymes from Trichoderma reesei for biofuels production