2038 – When microbes rule the Earth

Prospecting Microbial Genomes for Biomolecules and Their Applications

Bioactive molecules of microbial origin are finding increasing biotechnological applications. Their sources range from the terrestrial, marine, and endophytic to the human microbiome. These biomolecules have unique chemical structures and related groups, which enable them to improve the efficiency of the bioprocesses. This review focuses on the applications of biomolecules in bioremediation, agriculture, food, pharmaceutical industries, and human health.

Beyond planetary-scale feedback self-regulation: Gaia as an autopoietic system

The Gaia hypothesis states that the Earth is an instance of life. However, appraisals of it tend to focus on the claim that life is a feedback self-regulator that controls Earth's chemistry and climate dynamics, yet, self-regulation by feedbacks is not a definitive characteristic of living systems. Here, we consider the characterization of biological systems as autopoietic systems (causally organized to self-produce through metabolic efficient closure) and then ask whether the Gaia hypothesis is a tractable question from this standpoint. A proof-of-concept based on Chemical Organization Theory (COT) and the Zero Deficiency Theorem (ZDT) applied on a simple but representative Earth's molecular reaction network supports the thesis of Gaia as an autopoietic system. We identify the formation of self-producing organizations within the reaction network, corresponding to recognizable scenarios of Earth's history. These results provide further opportunities to discuss how the instantiation of autopoiesis at the planetary scale could manifests central features of biological phenomenon, such as autonomy and anticipation, and what this implies for the further development of the Gaia theory, Earth's climate modelling and geoengineering.

Future climates: Markov blankets and active inference in the biosphere

We formalize the Gaia hypothesis about the Earth climate system using advances in theoretical biology based on the minimization of variational free energy. This amounts to the claim that non-equilibrium steady-state dynamics-that underwrite our climate-depend on the Earth system possessing a Markov blanket. Our formalization rests on how the metabolic rates of the biosphere (understood as Markov blanket's internal states) change with respect to solar radiation at the Earth's surface (i.e. external states), through the changes in greenhouse and albedo effects (i.e. active states) and ocean-driven global temperature changes (i.e. sensory states). Describing the interaction between the metabolic rates and solar radiation as climatic states-in a Markov blanket-amounts to describing the dynamics of the internal states as actively inferring external states. This underwrites climatic non-equilibrium steady-state through free energy minimization and thus a form of planetary autopoiesis.

Carotenoids from the ripening bacterium Brevibacterium linens impart color to the rind of the French cheese, Fourme de Montbrison (PDO)

Rind color of some high-value PDO cheeses is related to the presence of carotenoids, but little is known about the structure of the pigmented compounds and their origin. Our objective was to describe the carotenoids extracted from the rind of a French cheese, Fourme de Montbrison, and to compare them with the pigments produced by a bacterial strain used as an adjunct culture in the cheese ripening process. Eleven carotenoids were detected in the cheese rinds or in the biomass of Brevibacterium linens. Most of the carotenoids from the rinds belonged to the aryl (aromatic) carotenoid family, including hydroxylated and non-hydroxylated isorenieratene. Chlorobactene, a carotenoid rarely found in food products, was also detected. Agelaxanthin A was identified in the cheese rinds as well as in the B. linens biomass. Occurrence of this compound was previously described in only one scientific publication, where it was isolated from the sponge Agela schmidtii.