Lignin is an important commercially produced polymeric material. It is used extensively in both industrial and agricultural activities. Recently, it has drawn much attention from the scientific community. It is abundantly present in nature and has significant application in the production of biodegradable materials. Its wide usage includes drug delivery, polymers and several forms of emerging lignin nanoparticles. The synthesis of lignin nanoparticles is carried out in a controlled manner. The traditional manufacturing techniques are costly and often toxic and hazardous to the environment. This review article highlights simple, safe, climate-friendly and ecological approaches to the synthesis of lignin nanoparticles. The changeable, complex structure and recalcitrant nature of lignin makes it challenging to degrade. Researchers have discovered a small number of microorganisms that have developed enzymatic and non-enzymatic metabolic pathways to use lignin as a carbon source. These microbes show promising potential for the biodegradation of lignin. The degradation pathways of these microbes are also described, which makes the study of biological synthesis much easier. However, surface modification of lignin nanoparticles is something that is yet to be explored. This review elucidates the recent advances in the biodegradation of lignin in the ecological system. It includes the current approaches, methods for modification, new applications and research for the synthesis of lignin and lignin nanoparticles. Additionally, the intricacy of lignin’s structure, along with its chemical nature, is well-described. This article will help increase the understanding of the utilization of lignin as an economical and alternative-resource material. It will also aid in the minimization of solid waste arising from lignin.

Background & Aims There are some studies indicating the effects of probiotic-containing foods or supplements on viral diseases. We aimed to conduct a rapid review of probiotics with specific emphasis on their potential for early administration in patients at greater risk of SARS-CoV-2 infection. Methods We searched on PubMed, EMBASE, Google Scholar, Science Direct, Scopus and Web of Science up to February 2021 to identify interventional and observational studies documenting the effects of probiotics strains on interleukins, virus titers, and antibody production with a focus on probiotic-containing foods (PROSPERO Registration ID. CRD42020181453). Results From a total of 163 records, 21 studies were classified into three domains based on the efficacy of probiotics on 1) the level of interleukins (n=7), 2) virus titers (n=2), and 3) interferon (IFN) and antibody production (n=12). The suppuration of pro-inflammatory interleukins and type I INF production seemed to be the main anti-viral effect of probiotics. Nine studies also indicated the beneficial effects of probiotics and fermented foods on viral diseases. Conclusion Based on evidence, some probiotic strains may be useful in viral infections; randomized trials are needed to confirm these findings.

While all groups are affected by the COVID-19 pandemic, the aged people as well as those with underlying chronic medical conditions are at the greatest risk. The higher adherence to refined carbohydrate diets, sweats, and saturated fats contributes to the prevalence of obesity and type 2 diabetes; these disorders increase the risk for severe COVID-19 morbidity and mortality. Fast food consumption activates the intrinsic immune system and impairs adaptive immunity, leading to chronic inflammation and impaired host defence against viruses. Furthermore, inflammatory responses caused by COVID-19 may have long-term costs in survived individuals, leading to chronic disorders such as dementia and neurodegenerative disease through neuroinflammatory mechanisms that are related to an unhealthy diet. Therefore, now more than ever, wider access to healthy foods should be a main concern and individuals should be aware of healthy eating habits to reduce COVID-19 complications.

BackgroundTyphoid fever is an acute systemic infection of humans caused by Salmonella enterica subspecies enterica serovar Typhi (S. Typhi). In chronic carriers, the bacteria survive the harsh environment of the gallbladder by producing biofilm. The phenotype of S. Typhi biofilm cells is significantly different from the free-swimming planktonic cells, and studies have shown that they are associated with antibiotic resistance, immune system evasion, and bacterial persistence. However, the mechanism of this transition and the events leading to biofilm formation are unknown. High throughput sequencing was performed to identify the genes involved in biofilm formation and to postulate the mechanism of action.ResultsPlanktonic S. Typhi cells were cultured using standard nutrient broth whereas biofilm cells were cultured in a stressful environment using high shearing-force and bile to mimic the gallbladder. Sequencing libraries were prepared from S. Typhi planktonic cells and mature biofilm cells using the Illumina HiSeq 2500 platform, and the transcriptome data obtained were processed using Cufflinks bioinformatics suite of programs to investigate differential gene expression between the two phenotypes. A total of 35 up-regulated and 29 down-regulated genes were identified. The identities of the differentially expressed genes were confirmed using NCBI BLAST and their functions were analyzed. The results showed that the genes associated with metabolic processes and biofilm regulations were down-regulated while those associated with the membrane matrix and antibiotic resistance were highly up-regulated.ConclusionsIt is proposed that the biofilm phenotype of S. Typhi allows the bacteria to increase production of the membrane matrix in order to serve as a physical shield and to adhere to surfaces, and enter an energy conservation state in response to the stressful environment. Conversely, the planktonic phenotype allows the bacteria to produce flagella and increase metabolic activity to enable the bacteria to migrate and form new colonies of infection. This data provide a basis for further studies to uncover the mechanism of biofilm formation in S. Typhi and to discover novel genes or pathways associated with the development of the typhoid carrier state.Electronic supplementary materialThe online version of this article (10.1186/s12864-017-4212-6) contains supplementary material, which is available to authorized users.

This study aimed to enhance production of polyhydroxybutyrate P(3HB) by a newly engineered strain of NSDG-GG by applying response surface methodology (RSM). From initial experiment of one-factor-at-a-time (OFAT), glucose and urea were found to be the most significant substrates as carbon and nitrogen sources, respectively, for the production of P(3HB). OFAT experiment results showed that the maximum biomass, P(3HB) content, and P(3HB) concentration of 8.95 g/L, 76 wt%, and 6.80 g/L were achieved at 25 g/L glucose and 0.54 g/L urea with an agitation rate of 200 rpm at 30 °C after 48 h. In this study, RSM was applied to optimize the three key variables (glucose concentration, urea concentration, and agitation speed) at a time to obtain optimal conditions in a multivariable system. Fermentation experiments were conducted in shaking flask by cultivation of NSDG-GG using various glucose concentrations (10-50 g/L), urea concentrations (0.27-0.73 g/L), and agitation speeds (150-250 rpm). The interaction between the variables studied was analyzed by ANOVA analysis. The RSM results indicated that the optimum cultivation conditions were 37.70 g/L glucose, 0.73 g/L urea, and 200 rpm agitation speed. The validation experiments under optimum conditions produced the highest biomass of 12.84 g/L, P(3HB) content of 92.16 wt%, and P(3HB) concentration of 11.83 g/L. RSM was found to be an efficient method in enhancing the production of biomass, P(3HB) content, and P(3HB) concentration by 43, 21, and 74%, respectively.