Industrial microbiology

The crucial first step in the biodegradation of polyethylene plastic is oxidation of the polymer. This has traditionally required abiotic pre-treatment, but now Bertocchini and colleagues report two wax worm enzymes capable of catalyzing this oxidation and subsequent degradation at room temperature.

Marine ecosystems are dominated by microbial communities. Inspired by the photoelectric conversion feature of the marine ecosystems, the authors design a four-species microbial community to mimic primary producer, primary degrader, and ultimate consumers, and show its ability to convert light into electricity for over one month.

CRISPR gene activation and inhibition has become a powerful synthetic tool for influencing the expression of native genes for foundational studies, cellular reprograming, and metabolic engineering. Here the authors demonstrate near leak-free, inducible expression of a polycistronic array containing up to 24 gRNAs from two orthogonal CRISPR/Cas systems.

Muconic acid is a platform chemical with wide industrial applicability. Here, the authors report efficient muconate production from glucose and xylose by engineered Pseudomonas putida strain using adaptive laboratory evolution, metabolic modeling, and rational strain engineering strategies.

Gene dosage-based expression upregulation suffers from instability and random gene integration. Here, the authors report HapAmp, a method that uses haploinsufficiency as evolutionary force to drive in vivo gene amplification, and demonstrate its applications in protein and biochemical production in yeast.

Domesticated industrial yeast strains are sterile, which hampers to breed strains with novel properties. Here, the authors employ the genetics paradigm return-to-growth to induce genome wide recombination in two sterile polyploid industrial yeasts and identify clones with superior biotechnological traits.

Product toxicity is one of the factors that hinder biofuel production. Here, the authors engineer the actin cytoskeleton to increase cell growth and production of n-butanol and medium-chain fatty acids in Saccharomyces cerevisiae.

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.

Microalgae are promising feedstock for oil production. The authors report that a transcription factor NobZIP77 can regulate oil synthesis by sensing the blue light, and explore these findings to greatly enhance oil productivity via genetic and process engineering in Nannochloropsis oceanica.

Microbial production of oleochemicals involves strategies of expressing thioesterase to narrow the substrate pool for the termination enzyme at the expense of one ATP. Here, the authors developed an alternative energy-efficient strategy to use of an acyl-ACP transacylase to produce medium chain oleochemicals in E. coli.

Here, the authors characterize the gut microbiome fermentation properties and therapeutic potential of chemically diverse synthetic glycans (SGs), showing they promote specific shifts in taxonomic and metabolite profiles, and exhibit therapeutic benefits in mouse models of colonic inflammation, together implying SGs as a potential avenue to treat disease by modulating the composition and metabolites produced by the gut microbiome.

Corynebacterium glutamicum is a major workhorse in industrial biomanufacturing of amino acids. Here, the authors employ CRISPR-assisted rational flux-tuning and CRISPRi screening of a L-proline exporter to covert a wild-type C. glutamicum to a hyperproducer of L-proline.

Growth limitation caused by mutual shading and the high harvest cost hamper algal biofuel production. Here, the authors overcome these two problems by designing a semi-continuous algal cultivation system and an aggregation-based sedimentation strategy to achieve high levels production of biomass and limonene.

The testing of engineered enzymes represents a bottleneck. Here the authors report a screening method combining microfluidics and mass spectrometry, to map the catalysis of a mutated enzyme, characterise the range of products generated and recover the sequences of variants with desired activities.

Returning from Mars to Earth requires propellant. The authors propose a biotechnology-enabled in situ resource utilization (bioISRU) process to produce a Mars specific rocket propellant, 2,3-butanediol, using cyanobacteria and engineered E. coli, with lower payload mass and energy usage compared to chemical ISRU strategies.

Here, the authors engineer microbial production of muscle titin fibers with highly desirable mechanical properties and provide structural analyses that explain the molecular mechanisms underlying high performance of this polymer with potential uses in biomedicine and textile industries, among others.

Cellulosic hydrolysates contain substantial amounts of acetate, which is toxic to fermenting microorganisms. Here, the authors engineer Baker’s yeast to co-consume xylose and acetate for triacetic acid lactone production from a hemicellulose hydrolysate of switchgrass.

Synthetic pathways represent a metabolic burden on host cells. Here the authors engineer Cra-binding sites to prevent misregulation in glycerol and carotenoid overproducing E. coli strains.

Esters can be used as fuels and specialty chemicals for food flavoring, cosmetic and pharmaceutical industries. Here, the authors systematically engineer clostridia, including discovery and deletion of prophages to increase strain stability, for the production of butyl acetate and butyl butyrate from corn stover at low cost.

Nicotinamide cytosine dinucleotide is an NAD mimic that can be used to mediate redox reactions. Here the authors design an NCD synthetase for the intracellular production of NCD.

3-Hydroxypropionic acid (3HP) is an important platform chemical. Here, the authors engineer Halomonas bluephagenesis by deleting newly identified degradation pathway and balancing redox state to achieve high level production of 3HP and its copolymer under open and unsterile conditions.

Industrial sugarcane ethanol fermentations are accomplished by a microbial community dominated by S. cerevisiae and co-occurring bacteria. Here, the authors investigate how microbial community composition contributes to community function and reveal the role of acetaldehyde in improving yeast growth rate and ethanol production.

The cost and complexity of whole genome sequencing limits its use in identifying and validating sequences used for genetic engineering and synthetic biology. Here the authors present Prymetime, an integrated workflow to sequence engineered strains and identify engineering in metagenomes.

Chondroitin sulfate (CS) is a type of sulfated glycosaminoglycan that is manufactured by extraction from animal tissues for the treatment of osteoarthritis and in drug delivery applications. Here, the authors report the development of single microbial cell factories capable of compete, one-step biosynthesis of animal-free CS production in E. coli.

Direct cloning of biosynthetic gene clusters is difficult due to their size and repetitive nature. Here, the authors present CAPTURE, which uses Cas12a and in vivo Cre-lox recombination for efficient cloning of gene clusters up to 113 kb, and demonstrate how this method can be used for large-scale discovery of novel natural products.

Loss-of-function experiments are used in metabolic engineering to understand and optimise metabolism. Here, the authors apply auxin inducible protein degradation to test different metabolic engineering strategies for improved terpenoid production in yeast.

Short-chain primary amines (SCPAs) are industrially important compounds that are commonly produced under harsh synthetic conditions. Here, the authors report a combination of retrobiosynthesis and precursor selection step for design of biosynthetic pathways leading to production of SCPAs, using valine decarboxylase-expressing Escherichia coli strains.

Alka(e)nes with chain lengths in C5-C23 range are ideal fuel components. Here, the authors report that high-titer production of alak(e)nes in pathway engineered Yarrowia lipolytica, which is enabled by the finding that acyl-CoA is another substrate of fatty acid photodecarboxylase (FAP).

The development of techniques capable of orchestrating the assembly of living cells into multicellular ensembles with synergistic and function is challenge. Here, the authors construct algal or algal/bacterial cells-based core shell-like structure based on aqueous two-phase system for synergic photosynthetic H₂ production.

The structural programmability and functionality of peptide materials can be leverage for various next-generation devices such as non-volatile memories. The authors report a proton-coupled mechanism in tyrosine-rich peptides for realizing multimodal memory devices.

Rare earth elements are used in electronics, but increase in demand could lead to low supply. Here the authors conduct experiments on the International Space Station and show microbes can extract rare elements from rocks at low gravity, a finding that could extend mining potential to other planets.

An imbalance between cell growth and bioproduction of engineered microbes often reduces production efficiency. Here, the authors report genetic code expansion-based cell growth and biosynthesis balance engineering to achieve high levels production of N-acetylglucosamine in E. coli and N-acetylneuraminic acid in B. subtilis.

Transcriptional biosensors represent powerful tools for the screening of vast strain libraries, but the broad ligand specificity of some transcriptional regulators (TRs) can prohibit such applications. Here authors present the engineering of a LysG-based biosensor with a focused ligand specificity to isolate L-histidine-producing strains.

Successful application of microbial community for bioproduction relies on the selection of appropriate heterotroph and phototroph partners. Here, the authors construct community metabolic models to guide strain selection and experimentally validate metabolic exchanges that sustain the heterotrophs in minimal media.

Halomonas bluephagenesis is a halophilic platform bacterium for next generation industrial biotechnology. Here, the authors employ a stimulus response-based flux-tuning method for coproduction of bioplastic PHB and ectoine under open unsterile and continuous growth conditions.

Bioproduction of hyaluronan needs increases in yield and greater diversity of the molecular weights. Here, the author increases hyaluronan production and diversifies the molecular weights through engineering the hyaluronan biosynthesis pathway and disruption of Corynebacterium glutamicum encapsulation caused by secreted hyaluronan.

Manipulation of genes controlling microbial shapes can affect bio-production. Here, the authors employ an optogenetic method to realize dynamic morphological engineering of E. coli replication and division and show the increased production of acetoin and poly(lactate-co-3-hydroxybutyrate).

Fermentation parameters of industrial processes are often not the ideal growth conditions for industrial microbes. Here, the authors reveal that young genes are more responsive to environmental stress than ancient genes using a new gene age assignment method and provide targeted genes for metabolic engineering.

Malate dehydrogenase (MDH) is one of the key enzymes for succinic acid (SA) bioproduction. Here, the authors report biochemical and structural analyses of various MDHs to reveal amino acids influencing the specific activity and susceptibility to substrate inhibition, and achieve industrial-level SA production.

Corn fiber is a difficult feedstock to utilize due to its recalcitrant hemicellulose. Here, the authors characterize the recalcitrant structures, isolate a new bacterium to consume the hemicellulose, identify its enzymes, and show the benefit with increased conversion of corn fiber to ethanol.

Combining genome mining and heterologous expression in a genetically tractable host can lead to bioactive natural products discovery and production. Here, the authors employ this strategy for new decalin-containing diterpenoid pyrenes production by expressing native, extended, and shunt pathways in Aspergillus oryzae.

Developing cyanobacteria as CO2-neutral cell factories relies on the knowledge of the regulation mechanisms for growth and metabolism. Here, the authors develop an inducible CRISPRi gene repression library in Synechocystis sp. PCC 6803 and screens genes potentially affecting growth and L-lactate tolerance and production.

Biosynthetic mechanism for the type 2 diabetes treatment drug acarbose is not fully revealed. Here, the authors show that shunt pathways and inefficient amino-deoxyhexose biosynthesis lead to 1-epi-valienol and valienol accumulation, and minimizing the flux to these shunt products can increase acarbose titer in Actinoplanes species.

Aspergillus fungi classified within the section Flavi include harmful and beneficial species. Here, Kjærbølling et al. analyse the genomes of 23 Flavi species, showing high genetic diversity and potential for synthesis of over 13,700 CAZymes and 1600 secondary metabolites.

Existing efforts have been focused on one of the elements in the automation of the design, build, test, and learn (DBTL) cycle for biosystems design. Here, the authors integrate a robotic system with machine learning algorithms to fully automate the DBTL cycle and apply it in optimizing the lycopene biosynthetic pathway.

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.

Microbial production of aromatic amino acid (AAA)-derived chemicals remains an outstanding metabolic engineering challenge. Here, the authors engineer baker’s yeast for high levels p-coumaric acid production by rewiring the central carbon metabolism and channeling more flux to the AAA biosynthetic pathway.

Production of tagatose, a sugar substitute, by isomerization of galactose suffers from unfavorable enzymatic kinetics, low enzyme stability, and low equilibrium constant. Here, the authors simultaneously overcome these limitations by encapsulating l-arabinose isomerase in permeabilized Lactobacillus plantarum.

Power densities of existing microbial biophotovoltaics (BPV) are low and unendurable. Here, the authors develop a BPV based on d-lactate mediated microbial consortium, which can generate an average power density of 135 mW·m⁻² for over 40 days in a spatial-temporal separation setup with medium replenishment.