Study on personalized microbial formulation during high-temperature aerobic fermentation of different types of food wastes

Utilization of gamma irradiated emulsified frying oil wastes as a carbon source for sustainable and economical production of bacterial cellulose membrane

BACKGROUND

Bacterial cellulose (BC) is a nanofibrils macromolecule that possesses unique properties and versatile applications in various fields. For commercial production, agro-industrial wastes were used as sustainable and cost effective alternative sources. Annually, a great amount of frying oil wastes are produced worldwide and disposed illegally resulting in huge environmental disasters. In this regard, the study aimed to investigate the effect of different concentration and increasing doses of gamma irradiation on the potential utilization of emulsified FOW as carbon source for BC production. In addition to tracking the behavior of SCOBY and BCM formation process in the presence of FOW.

METHODOLOGY

The effect of different factors including; concentrations of FOW, incubation period emulsification ratios and gamma irradiation on BC production were investigated and estimated gravimetrically. In addition, the manner of the cellulose membrane formation was closely tracked and was documented by photos.

RESULTS

The data proved that the symbiotic culture (SCOBY), has the ability to utilize frying oil wastes as a sole carbon source. Addition of 1% FOW resulted in (12.1%) increasing the BCM dry weight (2.81 to 3.15 gL- 1 in SWM, while the addition of 1% of the emulsified oil (FOW/E) recording (32.6%) increase in BC dry weight compared with control (5.33 and 4.02 gL- 1, respectively). Further increase in FOW/E concentration (> 2-5%) resulted in a significant gradual decreases (39%) in BC dry weight (from 5.33 to 3.25 gL- 1). Whereas, increasing the incubation period (21- days) resulted in a significant increase in BCM dry weight from 3.79 to 5.32 gL- 1 (40.4%). The effect of gamma irradiation (0-50 kGy) of FOW/E showed an increase in BCM dry weight (2.5%) at dose 10 kGy, while recorded (34.1%) increase compared with control (without FOW). The critical moments of SCOBY while struggling for surviving to gain the oxygen and nutrients required for BC biosynthesis in the presence of FOW have been documented photographically.

CONCLUSION

The present study positively contributes to the field of BC biosynthesis, where the FOW was added to the other agro-industrial wastes as a source of carbon for BC production, in addition to its potential application in the future in bioremediation for controlling environmental pollution.

Study and Application of Microbial Community in Biodegradation of Kitchen Waste Using High-Throughput Sequencing and Strain Isolation Techniques

Kitchen waste contains abundant starch, cellulose, lignin, and other organic compounds. This study investigated the microbial diversity of composite microbial communities capable of efficiently degrading kitchen waste, with a focus on the isolation of lignin-degrading strains. High-throughput sequencing on the Illumina MiSeq platform was utilized to analyze the diversity and community structure of bacteria and fungi in kitchen waste, enabling the identification of core microbiota. Approximately 60 strains, representing over 20 genera, were successfully isolated and identified using pure culture techniques. Comparative analysis of microbial diversity, based on high-throughput sequencing and traditional strain isolation methods, revealed that bacteria predominantly belonged to the phylum Firmicutes, while fungi were mainly classified into Ascomycota and Basidiomycota. These methods provided complementary insights into the composition and diversity of microbial communities. Among the culturable strains, three high-yield laccase-producing fungi-Schizophyllum commune, Alternaria alternata, and Coriolopsis trogii-were selected. The laccase genes Sc-lac and Aa-lac were synthesized and heterologously expressed in Pichia pastoris, resulting in laccase activities of 180 and 43 U L-1 in the supernatant, respectively. The laccases, Sc-lac and Aa-lac, were applied to degrade lignin, achieving degradation rates of 26.92% and 11.54%, respectively. The optimal temperature and pH for both laccases were 60°C and pH 3-3.5. These findings provide valuable insights into community structure analysis via high-throughput sequencing and the laboratory selection of cultivable strains. Furthermore, the screening and application of these enzymes and microorganisms contribute to reducing environmental pollution and promoting a sustainable, eco-friendly environment.

Sustainable management and valorization of biomass wastes using synthetic microbial consortia

In response to the persistent expansion of global resource demands, considerable attention has been directed toward the synthetic microbial consortia (SMC) within the domain of microbial engineering, aiming to address the sustainable management and valorization of biomass wastes. This comprehensive review systematically encapsulates the most recent advancements in research and technological applications concerning the utilization of SMC for biomass waste treatment. The construction strategies of SMC are briefly outlined, and the diverse applications of SMC in biomass wastes treatment are explored, with particular emphasis on its potential advantages in waste degradation, hazardous substances control, and high value-added products conversion. Finally, recommendations for the future development of SMC technology are proposed, and prospects for its sustainable application are discussed.

Isolation of starch and protein degrading strain Bacillus subtilis FYZ1-3 from tobacco waste and genomic analysis of its tolerance to nicotine and inhibition of fungal growth

Aerobic fermentation is an effective technique for the large-scale processing of tobacco waste. However, the specificity of the structure and composition of tobacco-derived organic matter and the toxic alkaloids in the material make it currently difficult to directly use microbial agents. In this study, a functional strain FYZ1-3 was isolated and screened from thermophilic phase samples of tobacco waste composting. This strain could withstand temperatures as high as 80°C and grow normally at 0.6% nicotine content. Furthermore, it had a strong decomposition capacity of tobacco-derived starch and protein, with amylase activity of 122.3  U/mL and protease activity and 52.3  U/mL, respectively. To further understand the mechanism of the metabolic transformation of the target, whole genome sequencing was used and the secondary metabolite gene cluster was predicted. The inhibitory effect of the strain on common tobacco fungi was verified using the plate confrontation and agar column methods. The results showed that the strain FYZ1-3 was Bacillus subtilis, with a genome size of 4.17  Mb and GC content of 43.68%; 4,338 coding genes were predicted. The genome was annotated and analyzed using multiple databases to determine its ability to efficiently degrade starch proteins at the molecular level. Moreover, 14 functional genes related to nicotine metabolism were identified, primarily located on the distinct genomic island of FYZ1-3, giving a speculation for its nicotine tolerance capability on the molecular mechanism. By mining the secondary metabolite gene cluster prediction, we found potential synthetic bacteriocin, antimicrobial peptide, and other gene clusters on its chromosome, which may have certain antibacterial properties. Further experiments confirmed that the FYZ1-3 strain was a potent growth inhibitor of Penicillium chrysogenum, Aspergillus sydowii, A. fumigatus, and Talaromyces funiculosus. The creation and industrial use of the functional strains obtained in this study provide a theoretical basis for its industrial use, where it would be of great significance to improve the utilization rate of tobacco waste.

Biodegradation of Oil by a Newly Isolated Strain Acinetobacter junii WCO-9 and Its Comparative Pan-Genome Analysis

Waste oil pollution and the treatment of oily waste present a challenge, and the exploitation of microbial resources is a safe and efficient method to resolve these problems. Lipase-producing microorganisms can directly degrade waste oil and promote the degradation of oily waste and, therefore, have very significant research and application value. The isolation of efficient oil-degrading strains is of great practical significance in research into microbial remediation in oil-contaminated environments and for the enrichment of the microbial lipase resource library. In this study, Acinetobacter junii WCO-9, an efficient oil-degrading bacterium, was isolated from an oil-contaminated soil using olive oil as the sole carbon source, and its enzyme activity of ρ-nitrophenyl decanoate (ρ-NPD) decomposition was 3000 U/L. The WCO-9 strain could degrade a variety of edible oils, and its degradation capability was significantly better than that of the control strain, A junii ATCC 17908. Comparative pan-genome and lipid degradation pathway analyses indicated that A. junii isolated from the same environment shared a similar set of core genes and that the species accumulated more specific genes that facilitated resistance to environmental stresses under different environmental conditions. WCO-9 has accumulated a complete set of oil metabolism genes under a long-term oil-contamination environment, and the compact arrangement of abundant lipase and lipase chaperones has further strengthened the ability of the strain to survive in such environments. This is the main reason why WCO-9 is able to degrade oil significantly more effectively than ATCC 17908. In addition, WCO-9 possesses a specific lipase that is not found in homologous strains. In summary, A. junii WCO-9, with a complete triglyceride degradation pathway and the specific lipase gene, has great potential in environmental remediation and lipase for industry.