Thermostable bacterial L-asparaginase for polyacrylamide inhibition and in silico mutational analysis.

The L-asparaginase (ASPN) enzyme has received recognition in various applications including acrylamide degradation in the food industry. The synthesis and application of thermostable ASPN enzymes is required for its use in the food sector, where thermostable enzymes can withstand high temperatures. To achieve this goal, the bacterium Bacillus subtilis was isolated from the hot springs of Tapovan for screening the production of thermostable ASPN enzyme. Thus, ASPN with a maximal specific enzymatic activity of 0.896 U/mg and a molecular weight of 66 kDa was produced from the isolated bacteria. The kinetic study of the enzyme yielded a Km value of 1.579 mM and a Vmax of 5.009 µM/min with thermostability up to 100 min at 75 °C. This may have had a positive indication for employing the enzyme to stop polyacrylamide from being produced. The current study has also been extended to investigate the interaction of native and mutated ASPN enzymes with acrylamide. This concluded that the M10 (with 10 mutations) has the highest protein and thermal stability compared to the wild-type ASPN protein sequence. Therefore, in comparison to a normal ASPN and all other mutant ASPNs, M10 is the most favorable mutation. This research has also demonstrated the usage of ASPN in food industrial applications.

Identification of coastal pesticide pollutants as potent inhibitors of Bacillus pasteurii urease mediated calcium carbonate precipitation: a computational approach.

Microbially induced calcite precipitation (MICP) through urease enzyme has attained a lot of recognition in various fields of civil engineering and geotechnology for stabilizing the strength of soil and various concrete materials. The activity of urease has been found to be affected by various factors like temperature, substrate concentrations, pH of the medium, presence of inhibitors, etc. Through this study, the outcome of the interaction of pesticides (commonly found in Indian coastal regions) on Bacillus pasteurii urease, a major organism reported for MICP studies has been investigated in silico. The results from the study revealed that the enzyme has higher interactions of -4.1, -3.2, and -3.4 kJ/mol with common pesticides like dichloro diphenyl dichloro ethane(DDD), dichloro diphenyl trichloroe thane (DDT), and methyl parathion of organochlorides and organophosphates class. From the molecular dynamics simulation analysis, complex 1 (DDD -receptor) has been found to have the highest and more compact structure followed by methyl parathion -receptor. Prime MM-GBSA analysis also revealed the highest binding energy of -27.8 kcal/mol with the protein and DDD. Thus, it can be inferred from the current study that pesticides, particularly, DDD, DDT, and methyl parathion present in the coastal areas may have an impact on urease. This interaction can result in the inhibition of the urease activity of B. pasteurii, thus preventing the biomineralization process. This study would be the first report on the computational approach to understanding the interaction of prominent pesticides on the coastal region and B. pasteurii urease.Communicated by Ramaswamy H. Sarma.

A New Perspective on Metabolites and Bioactive Compounds from Fungi.

Fungi play an important role in the solution to important global problems. Making use of processes and goods that are based on fungi can help promote sustainability by making the most efficient use of natural resources. Fungi stand apart from other organisms due to their extraordinary capacity to generate organic compounds. They are necessary for the psychological and physiological well-being of people worldwide. They are excellent producers of vitamins, pigments, hydrolytic enzymes, biofuels, organic acids, polysaccharides, and secondary metabolites such as antibiotics, anticancer treatments, hypocholesterolemic pharmaceuticals, and immunosuppressants. Other secondary metabolites include biofuels. In addition, polysaccharides are produced by them. We provide a condensed explanation of the significance of secondary metabolites in a variety of industries, such as the pharmaceutical industry, the food industry, the textile industry, and the transportation industry. In addition to providing a better understanding of biosynthetic regulation and the possibilities of genetic engineering, improved laboratory processes for the selection of nontoxigenic fungal strains have permitted the manufacture of larger quantities of safe commercial items. The significance of fungi in industrial settings is the topic that will be investigated in this review.

Antimicrobial peptides derived from microalgae for combating antibiotic resistance: Current status and prospects.

Microalgae are photosynthetic cell factories that produce a spectrum of bioactive compounds extensively used for various applications. Owing to the increase in antibiotic resistance among microbial pathogens, there is a significant thrust for identifying new treatment strategies, and antimicrobial peptides (AMPs) generation is one such method. These AMPs have multiple roles and are active against bacteria, fungi, and viruses. Such peptides synthesized in microalgae have a significant role in medical application, managing aquaculture-associated diseases, and the food industry. To increase their effectiveness and novel peptides, genetically modified microalgae are used as cell factories. With the advancement of new technologies like the CRISPR-Cas system, new avenues are opened for developing novel AMPs using microalgae. This review gives us insight into the various AMPs produced by microalgae and multiple technologies involved in creating such therapeutically essential molecules.

Bacterial diversity in the aquatic system in India based on metagenome analysis-a critical review.

Microbial analysis has become one of the most critical areas in aquatic ecology and a crucial component for assessing the contribution of microbes in food web dynamics and biogeochemical processes. Initial research was focused on estimating the abundance and distribution of the microbes using microscopy and culture-based analysis, which are undoubtedly complex tasks. Over the past few decades, microbiologists have endeavored to apply and extend molecular techniques to address pertinent questions related to the function and metabolism of microbes in aquatic ecology. Metagenomics analysis has revolutionized aquatic ecology studies involving the investigation of the genome of a mixed community of organisms in an ecosystem to identify microorganisms, their functionality, and the discovery of novel proteins. This review discusses the metagenomics analysis of bacterial diversity in and around different aquatic systems in India.

Biotechnological interventions in food waste treatment for obtaining value-added compounds to combat pollution.

Over the last few decades, the globe is facing tremendous effects due to the unnecessary piling of municipal solid waste among which food waste holds a greater portion. This practice not only affects the environment in terms of generating greenhouse gas emissions but when left dumped in landfills will also trigger poverty and malnutrition. This review focuses on the global trend in food waste management strategies involved in the effective utilization of food waste to produce various value-added products in a microbiology aspect, thereby diminishing the negative impacts caused by the unnecessary side effects of non-renewable energy sources. The review also detailed the efficiency of microorganisms in the production of various bio-energies as well. Further, recent attempts to the exploitation of genetically modified microorganisms in producing value-added products were enlisted. This also attempted to address food waste valorization techniques, the combined applications of various processes for an enhanced yield of different compounds, and addressed various challenges. Further, the current challenges involved in various processes and the effective measures to tackle them in the future have been addressed. Thus, the present review has successfully addressed the circular bio-economy in food waste valorization.

Diversity pattern of marine culturable heterotrophic bacteria in a region with coexisting upwelling and mud banks in the southeastern Arabian Sea.

Mud banks and upwelling are two important oceanographic features occurring along the southwest coast of India during the southwest monsoon period. The study region, Alappuzha lying on the southwest coast of India, is unique due to the co-existence of upwelling and mud banks during the monsoon (MON) season. Water samples were collected from three stations, M1, M2, and M3, from April to September 2014, at weekly/biweekly intervals to determine the total bacterial abundance, viable prokaryotic counts, and total plate counts, along with measurements on physico-chemical parameters. For determining the heterotrophic culturable bacterial diversity, water samples were collected during two seasons, monsoon and pre-monsoon (PRM), from three stations. Water samples were inoculated into two non-selective broths for enrichment, DNA was extracted, and next-generation sequencing analysis was performed using Illumina Miseq sequencing. The sequence analysis revealed that dominant communities were Proteobacteria, followed by Firmicutes and Fusobacteria. Proportions of Fusobacteria increased during monsoon and proportions of Firmicutes were high in premonsoon season. Among Proteobacteria, Gammaproteobacteri is presented more than 99% of all the classes, irrespective of seasons. Vibrio was the most dominant genus during both seasons. The presence of anaerobic genera such as Propionigenium and Cetobacterium at all the stations during MON indicated the presence of upwelled waters. The genus Stenotrophomonas was observed in the M2 station alone. This study provides an overview of the culturable heterotrophic bacterial communities in a region in the southeastern Arabian Sea with coexisting mud banks and upwelling. The results of this study were compared with a published report on culture-independent bacterial diversity (from environmental DNA) from the same region. The study demonstrates that the use of culture media underrepresented the phylogenetic diversity and selectively enriched the class Gammaproteobacteria alone.

Bioengineered microbes for soil health restoration: present status and future.

According to the United Nations Environment Programme (UNEP), soil health is declining over the decades and it has an adverse impact on human health and food security. Hence, soil health restoration is a need of the hour. It is known that microorganisms play a vital role in remediation of soil pollutants like heavy metals, pesticides, hydrocarbons, etc. However, the indigenous microbes have a limited capacity to degrade these pollutants and it will be a slow process. Genetically modified organisms (GMOs) can catalyze the degradation process as their altered metabolic pathways lead to hypersecretions of various biomolecules that favor the bioremediation process. This review provides an overview on the application of bioengineered microorganisms for the restoration of soil health by degradation of various pollutants. It also sheds light on the challenges of using GMOs in environmental application as their introduction may affect the normal microbial community in soil. Since soil health also refers to the potential of native organisms to survive, the possible changes in the native microbial community with the introduction of GMOs are also discussed. Finally, the future prospects of using bioengineered microorganisms in environmental engineering applications to make the soil fertile and healthy have been deciphered. With the alarming rates of soil health loss, the treatment of soil and soil health restoration need to be fastened to a greater pace and the combinatorial efforts unifying GMOs, plant growth-promoting rhizobacteria, and other soil amendments will provide an effective solution to soil heath restoration ten years ahead.

Statistical optimization of thermostable alkaline protease from Bacillus cereus KM 05 using response surface methodology.

OBJECTIVES: Proteases have gained great attention due to their enormous applications in food, tannery, detergent, photography and many other industries. Proteases rank third position in the production of enzymes. This paper targets to isolate a bacterium with high alkaline protease activity and optimization of its production conditions using Response Surface Methodology (RSM). RESULTS: A bacterium isolated from soil contaminated with detergent exhibited clearance zone on skim milk agar medium with a protease activity of 22 U/ml. The bacterial strain was identified as Bacillus cereus KM05 and optimization of its production conditions were performed using statistical methods. Further optimization with Box Behnken design resulted in an increase in protease activity by 1.5-fold (28.6 U/ml). The protease enzyme was thermotolerant up to 70 °C with stability towards alkaline pH (pH 9). The enzyme was not affected by most of the metal ions and solvents. Moreover, the protease was also compatible with six commercial detergents tested. Densitometric analysis of the destained fabric materials following the detergent-enzyme treatment, revealed a stain removal efficiency of 97%. CONCLUSION: The alkaline protease enzyme obtained was stable at different conditions with stain removal efficacy. Hence, the present alkaline protease could be used for detergent formulations.

Natural dye from Caesalpinia sappan L. heartwood for eco-friendly coloring of recycled paper based packing material and its in silico toxicity analysis.

The uses of natural dyes are getting popularized due to the increased awareness regarding the toxicity of many chemical colorants. The chemical colorants are being replaced by the natural colorants for the various industrial applications. The plant-based natural colorants are considered eco-friendly and toxic free. In the present study, we report a natural dye from the heartwood of Caesalpinia sappan suitable for paper based packing materials. This forms the first report on the study of natural dye obtained from the heartwood of C. sappan on paper material. The extracted dye had a good photostability and able to make imprints on recycled paper bags. Moreover, a significant inhibition of bacterial growth was observed at a higher dye concentration of 100 µg mL-1 against P. aeruginosa which was higher than the standard antibiotics. Growth inhibition was also observed in case of B. subtilis (22 ± 0.17 mm) and K. pneumonia (21 ± 0.53 mm) at 100 µg mL-1. The dye could be used in making medicated packing materials and have many other bio-potential which was validated through in silico toxicity analysis. The application of such natural dyes in paper material value addition will help in a cleaner and sustainable process during paper recycling.

Correction to: A cleaner process of deinking waste paper pulp using Pseudomonas mendocina ED9 lipase supplemented enzyme cocktail.

The correct unit in Table 2 is Lipase activity (U/g).

A cleaner process of deinking waste paper pulp using Pseudomonas mendocina ED9 lipase supplemented enzyme cocktail.

Lipase enzyme has a critical role in deinking process along with other lignocellulosic enzymes. In this paper, we try to demonstrate the role of lipase in the enzyme cocktail used for enzymatic deinking. For this, we identified a potential lipolytic bacterium, Pseudomonas mendocina ED9 isolated from elephant dung with a molecular weight of 35 kDa. During the Box-Benhken model optimization, a maximum lipase activity of 105.12 U/g, which was 12.36-fold higher than the initial enzyme activity and 1.3-fold higher than the activity obtained during the Plackett Burman design, was achieved. A maximum lipase activity of 105.12 U/g was obtained after optimization. Ammonium sulphate (60%) precipitation resulted in a specific activity of 68.19 U/mg with a 1.4-fold purification and yield of 64%. Lipase from P. mendocina ED9 exhibited a Km of 0.5306 mM and Vmax of 25.0237 µmol/min/mg. A Δ brightness of approximately 14.5% were achieved during the enzymatic deinking using cocktail comprised of cellulase, xylanase and lipase. This reports the significant role and efficacy of lipase in enzyme cocktails for deinking applications. This formulation will reduce the pollution and environmental toxicity of conventional chemical deinking.

Characterization of marine bacterial carbonic anhydrase and their CO2 sequestration abilities based on a soil microcosm.

The novel technology of biological carbon sequestration using microbial enzymes have numerous advantages over conventional sequestration strategies. In the present study, extracellular carbonic anhydrase (CA) producing bacteria were isolated from water samples in the Arabian Sea, India. A potential isolate, Bacillus safensis isolate AS-75 was identified based on 16S rDNA sequence analysis. The culture conditions suitable for CA production were 32 °C incubation temperature with 4% NaCl and 10 mM Zn supplementation. Experimental optimization of culture conditions enhanced enzyme activity to 265 U mL-1. CA specific gene was characterized and based on the analysis, the CA of B. safensis isolate AS-75 was a leucine (11.3%) with α-helices as the dominant component in its secondary structure. Based on soil microcosm studies, CA could sequester CO2 by 95.4% ± 0.11% in sterilized soil with enzyme microcosm. Hence, the application of enzyme was found to be more effective in removing CO2.

Photocatalytic degradation of synthetic dyes using iron (III) oxide nanoparticles (Fe2O3-Nps) synthesised using Rhizophora mucronata Lam.

Biosynthesis of nanoparticles through plant extracts is gaining attention due to the toxic free synthesis process. The environmental engineering applications of many metal oxide nanoparticles have been reported. In this study, iron oxide nanoparticles (Fe2O3-Nps) were synthesised using a simple biosynthetic method using a leaf extract of a mangrove plant Rhizophora mucronata through reduction of 0.01 M ferric chloride. Fe2O3-Np synthesis was revealed by a greenish colour formation with a surface plasmon band observed close to 368 nm. The stable Fe2O3-Np possessed excitation and emission wavelength of 368.0 and 370.5 nm, respectively. The Fourier-transform infrared spectral analysis revealed the changes in functional groups during formation of Fe2O3-Np. Agglomerations of nanoparticles were observed during scanning electron microscopic analysis and energy-dispersive X-ray spectroscopic analysis confirmed the ferric oxide nature. The average particle size of Fe2O3-Np based on dynamic light scattering was 65 nm. Based on transmission electron microscopic analysis, particles were spherical in shape and the crystalline size was confirmed by selected area electron diffraction pattern analysis. The synthesised Fe2O3-Np exhibited a good photodegradation efficiency with a reduction of 83 and 95% of phenol red and crystal violet under irradiation of sunlight and florescent light, respectively. This report is a facile synthesis method for Fe2O3-Np with high photodegradation efficiency.

Microbial diversity in a coastal environment with co-existing upwelling and mud-banks along the south west coast of India.

Upwelling and mud banks are two prominent oceanographic features in the coastal waters along the south west coast of India during the southwest monsoon (MON) season. The present study investigates the microbial diversity in the coastal environments of Alappuzha, India, where upwelling and mud banks co-exist. Water samples were collected from three stations, M1, M2, and M3, on a weekly basis to estimate the physico-chemical parameters and microbial abundance (MA). Presence of cold waters (< 26 °C) with high nitrate (6-8 µM) and low dissolved oxygen (5 µM) in the sub surface waters during monsoon (M) confirmed the presence of upwelling at all the three stations. Simultaneously, presence of unusually calm waters was seen at M2 alone during M indicating the formation of mud banks. The microbial diversity was determined from three stations, with distinct oceanographic conditions (M1: coastal reference station with only upwelling, M2: mud banks + upwelling, and M3: offshore reference station with only upwelling). The water samples were collected during two seasons, pre-monsoon (April) and M (July) and analysed using 16S rRNA-based Illumina high-throughput metagenomic sequencing. Proteobacteria was the most dominant phyla, followed by Bacteroidetes, Firmicutes, Cyanobacteria, Actinobacteria, and Verrucomicrobia in order, with variations in their relative abundance spatially and seasonally. Though the MA increased during M at all the stations, the relative abundance of most of the bacterial phyla except Proteobacteria decreased during M season. Interestingly, most of the sequences at M2 during mud banks were unclassified at the class level indicating the presence of unique microbial populations in this station. Prediction of metabolic activity revealed ammonia oxidation, nitrite reduction, sulphate reduction, xylan degradation, dehalogenation, chitin degradation, etc. as important functions. The metabolic activity throws light on the role of microbes in this environment thereby providing a system-scale perspective of microbial community interactions.

Process optimization and production kinetics for cellulase production by Trichoderma viride VKF3.

Microbial cellulases are the enzymes widely studied due to their enormous applications in biochemical industry. Among 12 fungal isolates isolated from mangrove plant debris and soil sample collected from Valanthakad Mangroves, Kerala, India, 3 of them were found to exhibit cellulolytic activity. Among them, the most potent isolate which exhibited maximum cellulolytic activity was identified as Trichoderma viride VKF3 [Gene bank accession number- JX683684.1] based on colony morphology, microscopic observation and molecular centeracterization using D1/D2 region amplification. The isolate T. viride VKF3 was found to be non-phytopathogenic against the selected plants. Neighbour joining tree depicted its least divergence rate from the root taxon HM466686.1. T. viride VKF3 was grown under dynamic carbon, nitrogen sources, pH and temperature of the medium to draw out the optimum conditions for cellulase production. Protein stability kinetics and biomass production was also studied upto 11(th) day of incubation. It was evident from the study, that dextrose and beef extract could be used as major carbon and nitrogen sources in submerged fermentation at pH 9.0 and incubation temperature of 25°C to get maximum CMCase yield. Optimum enzyme recovery period was identified between 5(th) to 9(th) days of incubation beyond which the enzyme activity was reduced. By comparing two fermentation methods, submerged fermentation was found to be the best for maximum enzyme production. But utilization of substrates like sugarcane bagasse and cassava starch waste in the SSF offers a better scope in biodegradation of solid waste contributing to solid waste management.