Systematic characterization of potential cellulolytic marine actinobacteria Actinoalloteichus sp. MHA15

The Study of Potentially Lignocellulolytic Actinobacteria Pseudonocardia sp. AI2

The search for microorganisms with potential for bioconversion of lignocellulose is now of immediate interest. Industrial waste is a source of various microorganisms. This paper describes results of the research of potentially lignocellulolytic actinobacteria isolated from activated sludge of the wastewater treatment plant of a pulp and paper mill located in Komi Republic (Russia). One strain of actinobacteria, AI2, was found to be sufficiently active in terms of degradation of lignocellulose-containing materials. Testing of the AI2 isolate demonstrated its ability to synthesize cellulase, dehydrogenase and protease to various extents. The AI2 strain was found capable of biosynthesizing cellulase to 5.5 U/ml. In case of solid-phase fermentation using treated softwood and hardwood sawdust, the content of main components changed most significantly in aspen sawdust: from initial concentration of 20.4% down to 15.6% for lignin, and from 50.6% down to 31.8% for cellulose. In case of liquid-phase fermentation, the content of lignin components decreased significantly in the treated aqueous medium that contained lignosulfonates: from initial concentration of 3.6 g down to 2.1g. Taxonomic study of the AI2 strain of actinobacteria confirmed that it belongs to the rare Pseudonocardia genus of actinomycetes. Based on the results of 16S rRNA sequencing, the AI2 strain is most similar to the species Pseudonocardia carboxydivorans.

A comprehensive review on strategic study of cellulase producing marine actinobacteria for biofuel applications

Every year, 180 billion tonnes of cellulose are produced by plants as waste biomass after the cultivation of the desired product. One of the smart and effective ways to utilize this biomass rather than burn it is to utilize the biomass to adequately meet the energy needs with the help of microbial cellulase that can catalytically convert the cellulose into simple sugar units. Marine actinobacteria is one of the plentiful gram-positive bacteria known for its industrial application as it can produce multienzyme cellulase with high thermal tolerance, pH stability and high resistant towards metal ions and salt concentration, along with other antimicrobial properties. Highly stable cellulase obtained from marine actinobacteria will convert the cellulose biomass into glucose, which is the precursor for biofuel production. This review will provide a comprehensive outlook of various strategic applications of cellulase from marine actinobacteria which can facilitate the breakdown of lignocellulosic biomass to bioenergy with respect to its characteristics based on the location/environment that the organism was collected and its screening strategies followed by adopted methodologies to mine the novel cellulase genome and enhance the production, thereby increasing the activity of cellulase continued by effective immobilization on novel substrates for the multiple usage of cellulase along with the industrial applications.

Marine Cellulases and their Biotechnological Significance from Industrial Perspectives

Marine microorganisms represent virtually unlimited sources of novel biological compounds and can survive extreme conditions. Cellulases, a group of enzymes that are able to degrade cellulosic materials, are in high demand in various industrial and biotechnological applications, such as in the medical and pharmaceutical industries, food, fuel, agriculture, and single-cell protein, and as probiotics in aquaculture. The cellulosic biopolymer is a renewable resource and is a linearly arranged polysaccharide of glucose, with repeating units of disaccharide connected via β-1,4-glycosidic bonds, which are broken down by cellulase. A great deal of biodiversity resides in the ocean, and marine systems produce a wide range of distinct, new bioactive compounds that remain available but dormant for many years. The marine environment is filled with biomass from known and unknown vertebrates and invertebrate microorganisms, with much potential for use in medicine and biotechnology. Hence, complex polysaccharides derived from marine sources are a rich resource of microorganisms equipped with enzymes for polysaccharides degradation. Marine cellulases' extracts from the isolates are tested for their functional role in degrading seaweed and modifying wastes to low molecular fragments. They purify and renew environments by eliminating possible feedstocks of pollution. This review aims to examine the various types of marine cellulase producers and assess the ability of these microorganisms to produce these enzymes and their subsequent biotechnological applications.

Halophilic and Halotolerant Actinomycetes of Sambhar Salt Lake, India: Screening and Optimization of Cellulolytic Activity

Actinomycetes are Gram-positive filamentous bacteria well known for the production of bioactive compounds. Recently, many halophilic habitats have been explored for isolation of actinomycetes that exhibit biotechnological potentials. In this investigation, a saline habitat of Rajasthan, Sambhar Salt Lake (SSL) was selected to study the actinomycetes population and Carboxy Methyl Cellulase (CMCase) production by native isolates. A total of sixteen actinomycete isolates, halotolerant and moderately halophilic, were obtained using culture-dependent methods and characterized morphologically and biochemically. They were identified as members of Streptomyces, Nocardiopsis, Pseudonocardia, Saccharospolyspora, and Microbispora. Streptomyces was the most dominating genus, followed by Nocardiopsis. Agar plate assay was used for screening the isolates for CMCase production. Thirteen were found to produce the enzyme, apparent by hydrolysis observed on media plates. The highest relative activity of 22.04 was shown by isolate SSL 14 identified as Nocardiopsis sp. by 16S rDNA sequencing studies and thus selected for further optimization studies. Maximum enzyme (1.08 ± 0.09 U/ml) was produced using medium containing Carboxy Methyl Cellulose (Carbon source) and yeast extract (nitrogen source) at 12% NaCl and pH 9.0, incubated at 30 °C for 96 h. Maximum CMCase production at high salt concentration and pH suggests that Nocardiopsis SSL 14 can be used for industrial processes that operate under excessive saline and alkaline conditions.

Marine Polysaccharides: Occurrence, Enzymatic Degradation and Utilization

Macroalgae species are fast growing and their polysaccharides are already used as food ingredient due to their properties as hydrocolloids or they have potential high value bioactivity. The degradation of these valuable polysaccharides to access the sugar components has remained mostly unexplored so far. One reason is the high structural complexity of algal polysaccharides, but also the need for suitable enzyme cocktails to obtain oligo- and monosaccharides. Among them, there are several rare sugars with high value. Recently, considerable progress was made in the discovery of highly specific carbohydrate-active enzymes able to decompose complex marine carbohydrates such as carrageenan, laminarin, agar, porphyran and ulvan. This minireview summarizes these achievements and highlights potential applications of the now accessible abundant renewable resource of marine polysaccharides.

Isolation, Characterization, and Efficacy of Actinobacteria Associated with Arbuscular Mycorrhizal Spores in Promoting Plant Growth of Chili (Capsicum flutescens L.)

Nowadays, microorganisms that display plant growth promoting properties are significantly interesting for their potential role in reducing the use of chemical fertilizers. This research study proposed the isolation of the actinobacteria associated with arbuscular mycorrhizal fungi (AMF) spores and the investigation of their plant growth promoting properties in the in vitro assay. Three actinobacterial strains were obtained and identified to the genus Streptomyces (GETU-1 and GIG-1) and Amycolatopsis (GLM-2). The results indicated that all actinobacterial strains produced indole-3-acetic acid (IAA) and were positive in terms of siderophore, endoglucanase, and ammonia productions. In the in vitro assay, all strains were grown in the presence of water activity within a range of 0.897 to 0.998, pH values within a range of 5–11, and in the presence of 2.5% NaCl for the investigation of drought, pH, and salt tolerances, respectively. Additionally, all strains were able to tolerate commercial insecticides (propargite and methomyl) and fungicides (captan) at the recommended dosages for field applications. Only, Amycolatopsis sp. GLM-2 showed tolerance to benomyl at the recommended dose. All the obtained actinobacteria were characterized as plant growth promoting strains by improving the growth of chili plants (Capsicum flutescens L.). Moreover, the co-inoculation treatment of the obtained actinobacteria and AMF (Claroideoglomus etunicatum) spores could significantly increase plant growth, contribute to the chlorophyll index, and enhance fruit production in chili plants. Additionally, the highest value of AMF spore production and the greatest percentage of root colonization were observed in the treatment that had been co-inoculated with Streptomyces sp. GETU-1.

Enzyme Bioprospection of Marine-Derived Actinobacteria from the Chilean Coast and New Insight in the Mechanism of Keratin Degradation in Streptomyces sp. G11C

Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes-Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes.

Update on Marine Carbohydrate Hydrolyzing Enzymes: Biotechnological Applications

After generating much interest in the past as an aid in solving structural problems for complex molecules such as polysaccharides, carbohydrate-hydrolyzing enzymes of marine origin still appear as interesting biocatalysts for a range of useful applications in strong interdisciplinary fields such as green chemistry and similar domains. The multifaceted fields in which these enzymes are of interest and the scarce number of original articles in literature prompted us to provide the specialized analysis here reported. General considerations from modern (2016-2017 interval time) review articles are at start of this manuscript; then it is subsequently organized in sections according to particular biopolymers and original research articles are discussed. Literature sources like the Science Direct database with an optimized W/in search, and the Espacenet patent database were used.