Environmental biotechnology

CRISPR gene drives are genetic elements capable of quickly spreading through populations and they offer promising solutions for curbing the spread of vector-borne diseases and controlling crop pest and invasive species populations. Here the authors present a method for overcoming resistance alleles “double-tap,” that encodes additional gRNAs in the gene drive that target the most common generated resistance alleles.

Microbial communities are responsible for biological wastewater treatment. Here, Dueholm et al. generate more than 5 million high-quality, full-length 16S rRNA gene sequences from wastewater treatment plants across the world to construct a database with a comprehensive taxonomy, providing insights into diversity and function of these microbial communities.

Biocontainment is a key to developing safe genetically-engineered microbes (GEMs). Here the authors demonstrate genetically stable CRISPR-based kill switches that control GEMs’ viability in animal hosts, enabling their safe biomedical applications.

Microalgae used for CO₂ removal in an industrial exhaust gas stream usually has low CO₂ tolerance. Here, the authors increase CO₂ tolerance by expressing a single H + -pump and enable microalgal valorization of industrial flue gas.

Experimental analysis of gene drive population dynamics has mostly been limited to small cage trials. Here the authors, to fill the gap between lab based studies and field studies, use large indoor cages and see population suppression without the emergence of resistant alleles

Culex mosquitoes are a global vector for insect-borne diseases, though progress with genetic tools lags behind other mosquito species. Here the authors present a Cas9-based toolkit and methods that could support future gene drive development in these mosquitoes.

Thioglycoligases have proved useful for bonding carbohydrates to non-sugar acceptors, however, the scope of these biocatalysts is usually limited. Here, the authors engineer a xylosidase into a thioglycoligase with the ability to form O-, N-, S- and Se- glycosides together with sugar esters and phosphoesters.

Interactions between electroactive bacteria and metal oxides are used for bioremediation. Here, the authors report on the application of Fe(III)-containing metal organic frameworks as substrates for bacterial growth which allow for remediation of lethal levels of chromium with high efficacy over several cycles.

Existing heavy metal bioremediation systems are mainly based on plants, which require long growing time in specific conditions. Here, the authors mimic the characteristics of plant hyperaccumulators to engineer more tractable baker’s yeast and achieve 10–100-fold higher accumulation of chromium, arsenic, or cadmium.

Marine woodborers can digest woody biomass without the help of gut microbiota but the mechanism has remained unclear. Here, the authors provide evidence that the woodborer’s respiratory protein hemocyanin plays a central role in wood digestion and may offer a route toward biorefining of woody plant biomass.

Poly(ethylene terephthalate) (PET) is a widely used plastic and its accumulation in the environment has become global problem. Here the authors report the crystal structure of a Ideonella sakaiensis PET-degrading enzyme and propose a molecular mechanism for PET degradation.

Cyanobacteria can be exploited to convert light energy into electrical current, however utilising them efficiently for power generation is a challenge. Here, the authors use a simple commercial inkjet printer to fabricate a thin-film paper-based biophotovoltaic cell capable of driving low-power devices.

Coalbeds produce natural gas, which has been observed to be enhanced by in situ microbes. Here, the authors add plant-derived carbohydrates (monosaccharides) to coal seams to be converted by indigenous microbes into natural gas, thus demonstrating a potential low carbon renewable natural gas resource.

Microbial fuel cells generate electricity from a variety of sources, however from methane only negligible electrical power has been reported so far. Here the authors convert methane into electricity using a synthetic consortium consisting of an engineered archaeal strain, microorganisms from methane-acclimated sludge, andGeobacter sulfurreducens.

Microbial fermentation yield is limited by CO₂ loss in glycolysis. Here, the authors engineered Clostridium ljungdahlii for the anaerobic, non-photosynthetic mixotrophy production of acetone, increasing carbon product yield while reducing CO₂emissions from a biogenic feedstock fermentation.