Firewood is a solid biofuel that is widely used for cooking in Mexico’s residential sector. This study seeks to identify relevant factors in firewood consumption patterns, and their implications for climate change, gender, and health, and for energy poverty in Mexico, by climate region and socioeconomic level. For this purpose, a statistical analysis was conducted of recently published official information. We estimate that a total of 31.3 million Mexicans—26% of the total population—use firewood, and we have identified three main types of users: (i) exclusive firewood users (30%); (ii) mixed firewood users using firewood as their primary fuel (18%) and (iii) mixed firewood users using firewood as their secondary fuel source (52%). Total consumption of firewood was estimated at 116.6 PJ, while estimated greenhouse gas emissions were 8.1 million tCO_2e. Out of all the households studied, 53% were in the tropical climate region; 59% were categorized as being in the “low” socioeconomic level; and 75% were in population centers comprising fewer than 2500 inhabitants. Some 68% of households do not pay for the acquisition of firewood, and for those households that do pay for the resource, estimated transactions total USD 286.9 million. Expenditures on firewood for energy represent up to 10% of household income. Finally, it was estimated that 15.7 million direct users of firewood are women who use the resource in three-stone fires, in which they expose themselves to health risks in doing so. In conclusion, main universal findings, the study’s limitations, and future research are presented.

Biorefineries (BRFs) that process the organic fraction of municipal solid waste and generate bioproducts and bioenergies have attracted attention because they can simultaneously address energy and environmental problems/needs. The objective of this article was to critically review the microbial production of hyaluronic acid (MPHA) and its production profile for its integration into a GBAER-type BRF (a type of BRF based on organic wastes) and to identify the environmental and economic sustainability aspects of the modified BRF that would confirm it as a sustainable option. It was found that the MPHA by selected strains of pathogenic Streptococci was moderate to high, although the trend to work with genetically transformed (GT) (innocuous) bacteria is gaining momentum. For instance, A GT strain of Corynebacterium glutamicum reached a maximum HA production of 71.4 g L⁻¹. MPHA reports that use organic wastes as sources of carbon (C) and nitrogen (N) are scarce. When alternative sources of C and N were used simultaneously, HA production by S. zooepidemicus was lower than that with conventional sources. We identified several knowledge gaps that must be addressed regarding aspects of process scale-up, HA industrial production, economic feasibility and sustainability, and environmental sustainability of the MPHA.

The objective of this study is to identify Mexican nontoxic ecotypes of Jatropha curcas with potential for a sustainable agriculture practice to produce biodiesel and food products through a methodology and criteria of sustainability. In a rural region of Morelos state in central México, nine Mexican ecotypes of Jatropha curcas were evaluated in an experimental plantation with minimal water resources and fertilization. The experimental trial was assessed in terms of (1) toxicity, (2) growth and survival of the plants, (3) yield of seed, (4) residual biomass production, (5) oil characteristics for biodiesel production, (6) nutrimental properties of the seeds, and (7) changes in the chemical properties of the soil. Finally, two outstanding nontoxic ecotypes were identified as the most suitable for the establishment of Jatropha curcas crops to produce biodiesel and, at the same time, for food products using the de-oiled endosperm cake, for energy production from the residual biomass and for improvement of soil properties in marginal lands of rural regions of Morelos state.

Within domestic food cooking, burning firewood in three-stone fires (TSF) is a common practice by more than 16 million users in the Mexican tropical climate region (CR-TR). This article aims to evaluate the implementation of improved firewood cookstoves (ICS) to replace TSF in the CR-TR by constructing firewood consumption scenarios covering 2018–2050. The results show that in CR-TR, with the implementation of ICS, the consumption of 354.95 PJ of firewood, 36.6 Mt of CO_2e, 1.29 Mt of CO, and 163.78 kt of PM_2.5 can all be avoided. The most important reduction in firewood consumption, CO_2e emissions and CO and PM_2.5 pollutants, occurs in exclusive firewood users and mixed users who utilize firewood as the primary fuel source, both of whom are low socioeconomic level in rural areas. Furthermore, most paying-for-firewood users often show negative mitigation costs and a high 50% IRR, while all non-paying-for-firewood users have mitigation costs ranging from 7.74 to 41.23 USD/tCO_2e. At the end of the results section, we perform a sensitivity analysis of the relevant parameters, which complements this study. Therefore, implementing ICS will contribute to the solution of climate change, deforestation, and facilitate the formulation of sustainable development policies for the most vulnerable population sector of the Mexican CR-TR.

Using information from an experimental planting of non-toxic Jatropha curcas (NTJC) with minimal water and fertilization resources on rural marginal soil the objective of this article is to determine the sustainability of this raw material for producing biodiesel and the possibilities for improving it through life-cycle assessment (LCA). Three production scenarios were studied: minimal resources (MR), which focuses on the obtaining of biodiesel; minimal resources and utilization of sub-products (MRUS), which includes the utilization of the residual products in order to produce food and solid biofuels, as well as biodiesel; and utilization of biofertilizers, flood irrigation, and sub-products (UBIS), which incorporates the use of bio-fertilizers and irrigation in the production system. This study includes the selection of six sustainability indicators, as well as indicators by means of LCA methodology Finally, a sustainability index (SI) for each scenario was determined on the basis of an index of environmental sustainability of energy products (IESEP). Our results indicated that the MR scenario yielded the lowest SI 0.673, while the MRUS scenario had the highest SI 0.956. It concludes that sustainability is greater when it utilizes minimal water and fertilization resources during the raw material production stage, and the residual products are used for food and energy products made possible by the non-toxic properties of Jatropha curcas.

Based on Life Cycle Assessment (LCA) and ISO standards, we compared the global environmental sustainability (ES) of two technologies that process the organic fraction of municipal solid waste (OFMSW) in Mexico. The first technology was a biorefinery (BRF) known as HMEZSNN-BRF (abbreviation for Hydrogen-Methane-Extraction-Enzyme-Saccharification/Nanoproduction Biorefinery); it produces the gas biofuels hydrogen (H) and methane (M), organic acids (E), enzymes (Z), saccharified liquors (S), and bionanobioparticles (BNBPs) in a nanoproduction stage (NN). The second technology was incineration with energy recovery (IER). An LCA was performed with a functional unit (FU) of 1000 kg of OFMSW. The BRF generates 166.4 kWh/FU (600 MJ) of net electricity, along with bioproducts such as volatile organic acids (38 kg), industrial enzyme solution (1087 kg), and BNBPs (40 kg). The IER only produces 393 net kWh/FU electricity and 5653 MJ/FU heat. The characterization potential environmental impacts (PEIs) were assessed using SimaPro software, and normalized PEIs (NPEIs) were calculated accordingly. We defined a new variable alpha and the indices σ-τ plane for quantifying the ES. The higher the alpha, the lower the ES. Alpha was the sum of the eighteen NPEIs aligned with the ISO standards. The contributions to PEI and NPEI were also analyzed. Four NPEIs were the highest in both technologies, i.e., freshwater and marine ecotoxicities and human non-carcinogenic and carcinogenic toxicities. For the three first categories, the NPEI values corresponding to IER were much higher than those of the BRF (58.6 and 8.7 person*year/FU freshwater toxicity; 93.5 and 13.6 marine ecotoxicity; 12.1 and 1.8 human non-carcinogenic toxicity; 13.7 and 13.9 human carcinogenic toxicity, for IER and the BRF, respectively). The total α values were 179.1 and 40.7 (person*yr)/FU for IER and the BRF, respectively. Thus, the ES of IER was four times lower than that of the BRF. Values of σ = 0.592 and τ = −0.368 were found; the point defined by these coordinates in the σ-τ plane was located in Quadrant IV. This result confirmed that the BRF in this work is more environmentally sustainable (with restrictions) than the IER in Mexico for the treatment of the OFMSW.