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Biosurfactants are amphiphilic compounds produced by bacteria either extracellularly or as a part of the cell membrane. Biosurfactants have had a profound impact on medical and pharmaceutical biotechnology. In our previous work, we isolated a new biosurfactant produced by Acinetobacter indicus M6 which reduces the surface tension of water from 72.0 to 39.8 mN/m and which showed thermophilic, halophytic and acidophilic stability. The chemical nature was found to be a class of glycolipoprotein. Here, our research presents the extracted biosurfactant’s anti-proliferative activity against lung cancer cells (A549), and anti-microbial and anti-biofilm activity against MRSA. The anti-tumour activity of biosurfactant against lung cancer cells was evaluated in terms of cell viability at different concentrations. The results showed a decrease in the percentage of lung cancer viable cells with increasing biosurfactant concentrations and incubation time, with a significant decrease being observed at 200 µg/ml concentration leading to cell proliferation inhibition at G1 phase. Treatment of biofilms for seven days at 500 µg/ml resulted in up to 82.5% biofilm disruption. Keywords: Biosurfactant, Acinetobacter indicus M6, Cell viability, Anti-proliferative activity, Anti-biofilm activity

Laccases are the green tools that can find potential applications in various industries. There are many reports available on laccases from plants and fungal sources but very few reports are available on bacterial laccases. Bacterial laccases show broad range of substrate specificity and it is easy to isolate and purify the bacterial extracellular laccases as compared to fungal laccases. Therefore, there are many advantages of bacterial laccases over fungal laccases.

Background Extracellular polysaccharides (ECPs) produced by biofilm-producing marine bacterium have great applications in biotechnology, pharmaceutical, food engineering, bioremediation, and bio-hydrometallurgy industries. The ECP-producing strain was identified as Acinetobacter indicus M6 species by 16S rDNA analysis. The polymer produced by the isolate was quantified and purified and chemically analyzed, and antioxidant activities have been studied. The face-centered central composite design (FCCCD) was used to design the model. Results The results have clearly shown that the ECP was found to be endowed with significant antioxidative activities. The ECP showed 59% of hydroxyl radical scavenging activity at a concentration of 500 μg/mL, superoxide radical scavenging activity (72.4%) at a concentration of 300 μg/mL, and DPPH˙ radical scavenging activity (72.2%) at a concentration of 500 μg/mL, respectively. Further, HPLC and GC-MS results showed that the isolated ECP was a heteropolymer composed of glucose as a major monomer, and mannose and glucosamine were minor monomers. Furthermore, the production of ECP by Acinetobacter indicus M6 was increased through optimization of nutritional variables, namely, glucose, yeast extract, and MgSO4 by “Response Surface Methodology”. Moreover the production of ECP reached to 2.21 g/L after the optimization of nutritional variables. The designed model is statistically significant and is indicated by the R2 value of 0.99. The optimized medium improved the production of ECP and is two folds higher in comparison with the basal medium. Conclusions Acinetobacter indicus M6 bacterium produces a novel and unique extracellular heteropolysaccharide with highly efficient antioxidant activity. GC-MS analyses elucidated the presence of quite uncommon (1→4)-linked glucose, (1→4)-linked mannose, and (→4)-GlcN-(1→) glycosidic linkages in the backbone. The optimized medium improved the production of ECP and is two folds higher in comparison with the basal medium. The newly optimized medium could be used as a promising alternative for the overproduction of ECP.

A novel approach of cellulase-based co-culture producing bioethanol using low-cost nutrient medium has been employed for the study, and docking strategies provided the information of cellobiose and cellotetraose inhibitors during cellulase production. The Acinetobacter species was isolated from termite gut and confirmed in 16s rDNA analysis. SDS-PAGE reveals the molecular weight of purified cellulose was 45 kDa. Cellulose activity was achieved maximum of 1.2 IU/mL at 48th hour of incubation, and about 80% of polysaccharides were converted into simple sugars. The enzyme activity was optimum at different physiological conditions like temperature at 37 °C, pH 7.0 and with 4% concentration of banana peduncle extract powder. Upon reaching maximum cellulolytic activity of 0.594 IU/mL, the percentage of ethanol produced from cellulosic hydrolysate using S. cerevisiae reached maximum ethanol (18.3 g/L) during 48 h of incubation. Cellulase produced by Acinetobacter indicus KTCV2 strain exhibits a short incubation period (48 h) and produces cellulase in broader pH and temperature ranges. Banana peduncle offers a cheapest raw material composed of cellulosic biomass in agricultural practices, which served as a good substrate for the production of ethanol.

CRISPR genome editing utilizes Cas9 nuclease and single guide RNA (sgRNA), which directs the nuclease to a specific site in the genome and makes a double-stranded break (DSB). Design of sgRNA for CRISPR-Cas targeting, and to promote CRISPR adaptation, uses a regulatory mechanism that ensures maximum CRISPR-Cas9 system functions when a bacterial population is at highest risk of phage infection. Acinetobacter baumannii is the most regularly identified gram-negative bacterium infecting patients. Recent reports have demonstrated that the extent of diseases caused by A. baumannii is expanding and, in a few cases, now surpasses the quantity of infections caused by P. aeruginosa. Most Acinetobacter strains possess biofilm-forming ability, which plays a major role in virulence and drug resistance. Biofilm bacteria use quorum sensing, a cell-to-cell communication process, to activate gene expression. Many genes are involved in biofilm formation and the mechanism to disrupt the biofilm network is still not clearly understood. In this study, we performed in silico gene editing to exploit the AbaI gene, responsible for biofilm formation. The study explored different tools available for genome editing to create gene knockouts, selecting the A. baumannii AbaI gene as a target. Keywords: AbaI, Acinetobacter baumannii, CHOPCHOP, Crispr-cas9, sgRNA

Biosurfactants produced by biofilm-forming bacteria have great applications in biotechnology, pharmaceutical, food engineering, bioremediation, and biohydrometallurgy industries. This study aimed to find out the bacteria that produce novel exopolymers (EPSs) which can find potential role in oil biodegradation. A screening procedure was performed to detect EPS-producing bacteria. The EPS producing isolate was identified as Acinetobacter species by 16S rDNA analysis. The polymer produced by the isolate has shown significant emulsification and surfactant activities, and the activities were compared to some of the commercial emulsifiers. The EPS has been partially characterized by FTIR analysis and has been proved to be a glycolipoprotein. This is one of the very few reports on Acinetobacter species producing EPS with surfactant properties.

An exopolysaccharide (EPS) was isolated from Bacillus coagulans RK - 02. Time course accumulation of EPS was studied with respect to biomass growth. The probiotic bacterium produces an EPS during exponential and stationary growth phases. Growth kinetics of the producer organism was characterized. The probiotic bacterium exhibited high affinity for the growth limiting substrate and hence grows at a higher specific growth rate. Based on HPLC and FTIR analyses, the EPS was found to be heteropolymer composed of galactose, mannose, fucose, glucose and glucosamine. The EPS showed significant emulsifying activities in different vegetable oils/hydrocarbon substrates. To the best of our knowledge, this is the first report on a bacterial EPS with fucose as a constituent sugar and also the first report on an EPS from B. coagulans .

Probiotic bacteria synthesize extracellular polysaccharides (EPSs) with commercially significant physiological and therapeutic activities. This important class of biomolecules is also characterized by their ability to remove reactive oxygen species (ROS) that are formed in the intestine by various metabolic reactions; hence, they exhibit antioxidant activities. Our probiotic bacterium, Bacillus coagulans RK-02, produces an EPS during the exponential and stationary growth phases when grown in a glucose mineral salts medium. The time course of EPS synthesis was studied with respect to biomass growth. The antioxidant and free radical scavenging potential of isolated EPS were studied by various methods, including the beta-carotene-linoleic acid model system, a superoxide radical scavenging assay using the PMS-NADH-nitroblue tetrazolium system, the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, a hydroxyl radical scavenging assay using the ascorbic acid-Cu(2+)-cytochrome c system and an in vitro microsome peroxidation inhibition study using a thiobarbituric acid assay. The antioxidant activities were compared to known antioxidants vitamin C and E, which were used as reference standards. The results showed that the EPS, which is a heteropolymer composed of four monosaccharides, produced by B. coagulans RK-02 had significant antioxidant and free radical scavenging activities.

Acne vulgaris (acne) is a chronic inflammatory disease prevalent among adolescents and adults, with significant psychological effects. The aetiology of acne is multifactorial. Several pathophysiological associations have been identified in which Propionibacterium acnes plays a major role. This bacteria primarily affects areas containing oil glands including the face, back and trunk, where it causes the formation of seborrhoea and inflammatory lesions. The treatment methods currently in place have side effects. A novel alternative method with no side effects is hence required. In this study, we report the synthesis of an exopolysaccharide (EPS)-producing bacterial-based nanoparticle as a stable biocompatible material for drug delivery. We then evaluated the effectiveness of EPS-based nanoparticle cream against P. acnes. Our results demonstrate that EPS nanoparticles have great potential as a safe and effective topical treatment for acne vulgaris and other associated infections. Electronic supplementary material The online version of this article (doi:10.1007/s13205-015-0359-5) contains supplementary material, which is available to authorized users.

The Gram-positive thin rods of a Bacillus species were identified and designated as Bacillus coagulans RK - 02 through the standard microbiological and biochemical characterization procedures, followed by data analysis and comparison with the characteristics given in Bergey’s manual of systematic bacteriology. The culture was further characterized and confirmed as Bacillus coagulans by 16S rDNA sequence analysis wherein about 755 nucleotides of 16S rDNA was amplified and cloned in pGEM-T vector and subsequently sequenced. Sequence was blasted against the nr database of NCBI. Multiple alignments were done with some selected and related sequences using Clustal W. Phylogenetic trees were drawn with the same software after the distances were determined by neighbor-joining algorithm. The in vitro studies on the probiotic properties demonstrated that our isolate could prove to be a potential probiotic with spore-forming and lactic acid-producing abilities coupled with acid and bile tolerance properties and antimicrobial action. In addition to these characteristics, the bacterium also produced enzymes such as amylase, cellulase, lipase, protease, lactase and catalase, which can help in improving digestion and overall health, alleviate lactose intolerance and remove oxidative stresses, required for the well-being of the consumers. In our previously reported studies, an exopolysaccharide (EPS), a probioactive molecule produced by the same bacterium, showed very significant antioxidant, antihyperglycemic and emulsification activities. Thus, Bacillus coagulans RK - 02 is a well-characterized promising probiotic for its potential commercial applications to pharmaceutical, nutraceutical and functional food formulations with care-free storage.

The management of the generated waste is a major problem in developing countries. The waste generated in the agroprocessing has been used as sources of nutrients for the microbes. In the present study, a medium has been formulated with banana fruit stalk and the microbial growth was monitored. Growth and biomass production was examined on banana stalk agar (BSA) and broth (BSB), banana stalk dextrose agar (BSDA) and broth (BSDB) using commercial potato dextrose agar (PDA) and broth (PDB) as control. It was observed that the good microbial growth was observed when compared to that of other conventional growth media. The weight of the Aspergillus niger biomass in BSDB was 1.8 g after 4 weeks of growth and the weight of the biomass in PDB was 0.9 g. The remarkable growth on BSDB may be attributed that the banana stalk is highly rich in nutrients.

In Saccharomyces cerevisiae, proteins with misfolded lumenal, membrane, and cytoplasmic domains are cleared from the endoplasmic reticulum (ER) by ER-associated degradation (ERAD)-L, -M, and -C, respectively. ERAD-L is N-glycan-dependent and is characterized by ER mannosidase (Mns1p) and ER mannosidase-like protein (Mnl1p), which generate Man(7)GlcNAc(2) (d1) N-glycans with non-reducing α1,6-mannosyl residues. Glycoproteins bearing this motif bind Yos9p and are dislocated into the cytoplasm and then deglycosylated by peptide N-glycanase (Png1p) to yield free oligosaccharides (fOS). Here, we examined yeast fOS metabolism as a function of cell growth in order to obtain quantitative and mechanistic insights into ERAD. We demonstrate that both Png1p-dependent generation of Man(7-10)GlcNAc(2) fOS and vacuolar α-mannosidase (Ams1p)-dependent fOS demannosylation to yield Man(1)GlcNAc(2) are strikingly up-regulated during post-diauxic growth which occurs when the culture medium is depleted of glucose. Gene deletions in the ams1Δ background revealed that, as anticipated, Mns1p and Mnl1p are required for efficient generation of the Man(7)GlcNAc(2) (d1) fOS, but for the first time, we demonstrate that small amounts of this fOS are generated in an Mnl1p-independent, Mns1p-dependent pathway and that a Man(8)GlcNAc(2) fOS that is known to bind Yos9p is generated in an Mnl1p-dependent, Mns1p-independent manner. This latter observation adds mechanistic insight into a recently described Mnl1p-dependent, Mns1p-independent ERAD pathway. Finally, we show that 50% of fOS generation is independent of ERAD-L, and because our data indicate that ERAD-M and ERAD-C contribute little to fOS levels, other important processes underlie fOS generation in S. cerevisiae.

An exopolysaccharide (EPS) was isolated from Bacillus coagulans RK-02 and purified by size exclusion chromatography. The purified, homogeneous EPS had an average molecular weight of ∼3 × 10⁴ Da by comparison with FITC-labeled dextran standards. In vivo evaluations showed that, like other reported polysaccharides, this EPS displayed significant antioxidant activity. FTIR spectroscopy analysis showed the presence of hydroxy, carboxy, and α-glycosidic linkages and a mannose residue. GC analysis indicated that the EPS was a heteropolymer composed of glucose, mannose, galactose, glucosamine, and fucose as monomeric constituent units. Partial elucidation of the structure of the carbohydrate biopolymer based on GC-MS and NMR analysis showed the presence of two unique sets of tetrasaccharide repeating units that have 1→3 and 1→6 glycosidic linkages. This is also the first report of a Gram-positive bacterial polysaccharide with both fucose as a sugar monomer and 1→3 and 1→6 glycosidic linkages in the molecular backbone.