With the development of bioinspired green solutions for sustainable construction over the past two decades, bio-cementation, which exploits the naturally occurring phenomenon of calcium carbonate precipitation in different environments, has drawn a lot of attention in both building construction and soil stabilization. Various types of microorganisms, along with specific enzymes derived from these microorganisms, have been utilized to harness the benefits of bio-cementation. Different application methods for incorporating this mechanism into the production process of the construction material, as well as a variety of experimental techniques for characterizing the outcomes of bio-cementation, have been developed and tested. Despite the fact that the success of bio-cementation as a sustainable method for construction has been demonstrated in a significant body of scientific literature at the laboratory scale, the expansion of this strategy to construction sites and field application remains a pending subject. The issue may be attributed to two primary challenges. Firstly, the complexity of the bio-cementation phenomenon is influenced by a variety of factors. Secondly, the extensive body of scientific literature examines various types of microorganisms under different conditions, leading to a wide range of outcomes. Hence, this study aims to examine the recent advancements in utilizing the most commonly employed microorganism, Sporosarcina pasteurii, to emphasize the significance of influential factors identified in the literature, discuss the findings that have been brought to light, and outline future research directions toward scaling up the process.

With a view toward the application of highly hygroscopic polymers as a humidity responsive self-actuator, the evaluation of the real time moisture concentration in the material becomes a priority. In this paper, the moisture diffusion process in a cellulose acetate (53.3% of acetylation) has been studied. Membranes of cellulose acetate (thickness within the range 66–200 µm) have been prepared, and the moisture absorption at room temperature and at a different relative humidity (RH within the range 21–53%) has been monitored. An analytical model has been used to describe the observed non-Fickian sigmoidal behavior of moisture diffusion. A relaxation factor (β) of about 0.026 s⁻¹and a moisture diffusion coefficient (D) of 3.35 × 10^–6mm²/s have been determined. At constant room temperature, the moisture concentration at saturation (C_sat) has shown a linear relation with relative humidity. The identified values β, D and C_satof the analytical model have been used as input for the finite element simulation of the non-Fickian diffusion. The reliability of the finite element simulations has been confirmed with a second set of experiments.

As a result of the exponential growth in the production of plastics and their extended degradation period, strong environmental concerns in association with the disposal of plastic waste have emerged. Pursuing sustainable solutions for managing plastic waste has led to significant interest in plastic biodegradation research, with a specific focus on biodeterioration facilitated by microorganisms. The biodeterioration of plastic by microorganisms is a complex phenomenon that can be influenced by a variety of environmental factors such as humidity, temperature, and pH, as well as polymer properties such as molecular structure, molecular weight, and crystallinity. Toward a better understanding of this phenomenon for resolving the issue of plastic waste, this review article focuses on the biodeterioration of synthetic polymers, in particular aliphatic polyesters and polyolefins, through the enzymatic activities of microorganisms. First, the mechanism of polymer biodegradation via enzymatic activity is discussed, followed by the physical properties of polymers and environmental conditions that influence their biodegradability rates. Then, an overview of experimental approaches and standardized protocols used to assess the biodegradability of polymers by these degrading agents is provided. Finally, current developments in employing biodeterioration for the degradation of aliphatic polyesters and polyolefins are reviewed. The review concludes with a discussion on the complexity of biodegradation by microorganisms, the necessity of proper engineering of polymer properties during production to enhance their biodegradability, and the need for further research to discover sustainable and environmentally acceptable alternatives.

Exploiting materials with the ability to respond to the environmental stimuli is experiencing an enormous research interest. In particular, polymers that are sensitive to the changes of humidity levels attract great attention as self-actuators. The sensitivity of these materials to the level of moisture is expressed by their hygroscopic properties, namely, the coefficient of hygroscopic expansion. In this context, this study details the effect of moisture absorption on cellulose acetate membranes, as potential material for humidity-responsive self-actuators. The aim is two-fold. The first deals with the evaluation of the coefficient of hygroscopic expansion (α) through the determination of the absorbed moisture concentration at saturation (C_sat) and the relevant moisture absorption induced strain (ε_hygro). The second assesses the accuracy of a finite element modeling in describing the coupling of moisture absorption in cellulose acetate membranes and the corresponding dimensional variation, using the material properties experimentally measured. The experimentally measured C_sat and ε_hygro resulted a non-linear dependency on relative humidity. Also the coefficient of hygroscopic expansion (α = C_sat /ε_hygro) resulted to have a non-linear dependency on the relative humidity, as well. By this input, numerical simulations were performed for different relative humidity levels, showing accurate description of experimental data.

Over the last two decades, biocementation as a sustainable method for producing self-healing cementitious materials has received a lot of attention in construction, soil stabilization, and wind-induced erosion industries. Despite advancements in the experimental characterization of this phenomenon, computational modeling of this biochemical process has not significantly advanced due to its complexity and the interrelated parameters involved. This study introduces a computational model in COMSOL Multiphysics^® to simulate calcium carbonate (CaCO ₃ ) precipitation by Sporosarcina pasteurii. A theoretical background on the interconnected parameters governing the precipitation process and on the concurrent chemical reactions involved is presented. The workflow and sequential implementation of input parameters are detailed. The model considers the impact of calcium and urea concentrations, alongside the initial pH level (ranging from 0 to 14) and the pH fluctuations induced by by-product generation during the biocementation process, at a constant temperature. The capability of the model to foresee CaCO ₃ concentration and ultimate pH level is evaluated by comparing the computational outcomes with empirical data obtained from established literature sources. The coefficient of determination, R², exceeding 0.99 indicates a strong correlation between experimental and numerical data, demonstrating the model’s high accuracy in predicting the quantities of calcium carbonate and other biocementation products and by-products. The influence of the initial pH of the environment on the pH variation of the system during the precipitation process was simulated and compared to actual data available in the literature, suggesting that the model can accurately predict the kinetic of biocementation. Through a parametric study, an environment with an initial pH between 4 and 10 was found to be the most favorable for biocementation by S. pasteurii.

The future of Mars colonization hinges on the ability to construct durable infrastructure using locally available resources. Given the high cost and logistical complexity of transporting construction materials to Mars, the development of autonomous in situ resource utilization (ISRU) technologies is imperative. This perspective article explores the potential of biomineralization as a low-energy, sustainable alternative to conventional construction methods, such as Portland cement and thermal sintering approaches proposed for lunar applications, which are often energy-intensive and constrained by material specificity. Following an assessment of the chemical composition of Martian regolith, its suitability as a substrate for various biomineralization pathways, particularly those aligned with ISRU constraints, is evaluated. Special emphasis is placed on identifying biological pathways that are not only metabolically compatible with Martian geochemistry but can also function as a co-culture, mutually supporting each other’s survival and activity under Martian environmental stresses. The most promising microbial consortia for biocementation are proposed for future extraterrestrial construction applications. The integration of robotics and automation in biocementation-based additive manufacturing using Martian regolith as a construction feedstock is discussed. Advanced robotic systems equipped with multi-axis extrusion nozzles, sensor suites, and real-time flow control are proposed for the construction of structurally resilient geometries on Mars. As a flexible, scalable, and ISRU-compatible technology, biocementation holds promise not only for infrastructure construction but also for integrated resource cycles, producing oxygen and ammonia as byproducts. Biocementation-based ISRU construction represents a synergistic pathway toward sustainable human presence on Mars, enabling robotic fabrication of critical infrastructure from locally available materials.