Characterization of cattle fecal Streptomyces strains converting cellulose and hemicelluloses into reducing sugars

Taxonomic and metabolic diversity of Actinomycetota isolated from faeces of a 28,000-year-old mammoth

Ancient environmental samples, including permafrost soils and frozen animal remains, represent an archive with microbial communities that have barely been explored. This yet unexplored microbial world is a genetic resource that may provide us with new evolutionary insights into recent genomic changes, as well as novel metabolic pathways and chemistry. Here, we describe Actinomycetota Micromonospora, Oerskovia, Saccharopolyspora, Sanguibacter and Streptomyces species were successfully revived and their genome sequences resolved. Surprisingly, the genomes of these bacteria from an ancient source show a large phylogenetic distance to known strains and harbour many novel biosynthetic gene clusters that may well represent uncharacterised biosynthetic potential. Metabolic profiles of the strains display the production of known molecules like antimycin, conglobatin and macrotetrolides, but the majority of the mass features could not be dereplicated. Our work provides insights into Actinomycetota isolated from an ancient source, yielding unexplored genomic information that is not yet present in current databases.

Multiple strategies for the development of multienzyme complex for one-pot reactions

The main intention in the modern era is to make life and activities on earth more comfortable by adding necessary products through biological machinery. Millions of tons of biological raw materials and lignocellulosic biomass are wasted by burning each year without providing benefits to living organisms. Instead of being the cause of disturbing the natural environment by increasing global warming and pollutants worldwide, now, it is the need of the hour to develop an advanced strategy to utilize these biological raw materials to produce renewable energy resources to meet the energy crisis. The review presents the idea of multiple enzymes in one step to hydrolyze complex biomaterials into useful products. The paper discusses how multiple enzymes are arranged in a cascade for complete hydrolysis of raw material in one-pot to prevent multistep, time consuming, and expensive methods. Furthermore, there was the immobilization of multiple enzymes in a cascade system with in vitro and in vivo conditions for reusability of enzymes. The role of genetic engineering, metabolic engineering, and random mutation techniques is described for the development of multiple enzyme cascades. Techniques that are involved in the improvement of native strain to recombinant strain for the enhancement of hydrolytic capacity were used. The preparative steps, before enzymatic hydrolysis like acid, and base treatment methods are more effective for improving the hydrolysis of biomass by multiple enzymes in a one-pot system. Finally, the applications of one-pot multienzyme complexes in biofuel production from lignocellulosic biomass, biosensor production, medicine, food industry, and the conversion of biopolymers into useful products are described.

Biodegradation of wheat straw by Ochrobactrum oryzae BMP03 and Bacillus sp. BMP01 bacteria to enhance biofuel production by increasing total reducing sugars yield

Pretreatment is a vital step to enhance the yield of total reducing sugars and biofuel production from lignocellulose biomass. An effective new lignin-degrading and polysaccharide-hydrolyzing bacteria, Ochrobactrum oryzae BMP03 and Bacillus sp. BMP01 strains, were isolated and identified from wood-feeding termite's guts. Wheat straw was biodelignified by Ochrobactrum oryzae BMP03 bacteria strains to degrade lignin and to release the trapped cellulose and hemicellulose. The biodelignified wheat straw was hydrolyzed by Bacillus sp. BMP01 strains. Ochrobactrum oryzae BMP03-Bacillus sp. BMP01 consortia were also performed to analyze the effect of the simultaneous system. It was shown that the production of total reducing sugars in a separate hydrolysis system by Bacillus sp. BMP01 strain achieved 439 mg/g at 16 days of hydrolysis time, which is 9.45% higher than the simultaneous system. About 44.47% lignin was degraded by the Ochrobactrum oryzae BMP03 strain after 16 days of biotreatment. This also contributed for increment in cellulose content by 22.38% and hemicellulose content by 18.64%. The simultaneous system converted 368 mg of reducing sugars/g of wheat straw. Separate biodelignification and hydrolysis have an advantage over the simultaneous system in terms of hydrolysis efficiency and vice versa in terms of biotreatment time. Scanning electron microscope, mid-infrared analysis by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis confirmed the change in composition due to biotreatment. The biotreatment improved hydrolysis efficiency, which reduces the cost of biofuel production and increases the yield of biofuel. These results indicate the possibilities of biofuel production from wheat straw by employing Ochrobactrum oryzae BMP03 and Bacillus sp. BMP01 bacteria strains.

Immunosuppressants produced by Streptomyces: evolution, hygiene hypothesis, tumour rapalog resistance and probiotics

Resistance to a drug and the suppression of inflammatory disorders with immunosuppressive drugs might have happened upon exposure to natural compounds during evolution. Streptomycetes are soil bacteria, but they produce therapeutic drugs. They have been reported to be the low-abundant members of mucosal microbiomes with a higher prevalence in nonhumans ingesting soil compared with humans. Their lower abundance in the human microbiome might be the representations of our current hygienic lifestyle. We suggest that the Streptomyces bacteria producing antiproliferative/immunosuppressive compounds (e.g., rapamycin and tacrolimus) contribute to the rapalog resistance of certain mucosal tumours (e.g., colon cancer) and the 'hygiene hypothesis'. If so, the shortage of exposure to these compounds in the current lifestyle might be an underlying reason for the increase of inflammatory diseases, such as inflammatory bowel diseases (IBD). An investigation on adding certain Streptomycetes (e.g., S. hygroscopicus and S. tubercidicus) to the list of probiotics against inflammatory diseases would be an interesting research area in the future.

Resuscitation of viable but non-culturable bacteria to enhance the cellulose-degrading capability of bacterial community in composting

Nowadays, much of what we know regarding the isolated cellulolytic bacteria comes from the conventional plate separation techniques. However, the culturability of many bacterial species is controlled by resuscitation‐promoting factors (Rpfs) due to entering a viable but non‐culturable (VBNC) state. Therefore, in this study, Rpf from Micrococcus luteus was added in the culture medium to evaluate its role in bacterial isolation and enhanced effects on cellulose‐degrading capability of bacterial community in the compost. It was found that Proteobacteria and Actinobacteria were two main phyla in the compost sample. The introduction of Rpf could isolate some unique bacterial species. The cellulase activity of enrichment cultures with and without Rpf treatment revealed that Rpf treatment significantly enhanced cellulase activity. Ten isolates unique in Rpf addition displayed carboxymethyl‐cellulase (CMCase) activity, while six isolates possessed filter paper cellulase (FPCase) activity. This study provides new insights into broader cellulose degraders, which could be utilized for enhancing cellulosic waste treatment.