Prakasan Priji

Production, optimization, and partial purification of lipase from Pseudomonas sp. strain BUP6, a novel rumen bacterium characterized from Malabari goat

This study introduces a novel bacterium—Pseudomonas sp. strain BUP6—isolated from the rumen of the Malabari goat with efficiency for producing lipase. It showed significant production of lipase when grown in a newly designed basal medium, supplemented with vegetable oil. Suitability of five vegetable oils such as groundnut oil, coconut oil, olive oil, sunflower oil, and palm oil as inducer for the production of lipase was examined, and groundnut oil supported the highest production of lipase (96.15 U/mL). Various physical parameters required for the maximum production of lipase were statistically optimized. Plackett–Burmann design was employed to study the interactive effects of physical parameters and found that temperature, agitation, and pH effected the production of lipase significantly. The optimum conditions for lipase production (37 °C, 200 rpm, and pH 6.9) were detected by Box–Behnken design and response surface methodology, which resulted in the 0.3‐fold increase (i.e., 126 U/mL) of the lipase activity over the unoptimized condition. The apparent molecular mass of partially purified lipase was 35 kDa, as judged by SDS‐PAGE; the activity of lipase was also confirmed by native PAGE. Thus, this study focuses on the need for the exploitation of rumen microbes for the production of industrially significant and human‐friendly biomolecules to meet the future needs.

Candida tropicalis BPU1, a novel isolate from the rumen of the Malabari goat, is a dual producer of biosurfactant and polyhydroxybutyrate

This unique study reports a new strain (BPU1) of Candida tropicalis isolated from the rumen of the Malabari goat, showing dual production of biosurfactant and polyhydroxybutyrate. C. tropicalis strain BPU1, a facultative anaerobe, was tuned to become an aerobe in specially designed flask, the Benjamin flask. The puffy circular colonies were smooth, white‐to‐cream in colour, with pseudo‐filaments. The strain fermented glucose, sucrose, maltose and dextrose, but not lactose and cellulose. It assimilated (NH4)2SO4, peptone, glycine and arginine, but not NaNO3, as the nitrogen source. Interestingly, it utilized groundnut oil (up to 0.3%) in a specially designed basal mineral salt medium (BSM). Its capability for dual production of a biosurfactant and a polyhydroxybutyarate (PHB) was explored by various methods from the BSM–oil medium. Extracted biosurfactant from 6 day‐old culture was biochemically characterized as a complex of lipid and carbohydrate with an Rf value of 0.88 by thin layer chromatography. Its PHB production was confirmed by specific staining methods with Nile blue sulphate, Sudan black B and Sudan 3. Briefly, this first‐ever report gives ample physical evidence for the dual production of a glycolipid (biosurfactant) and PHB by C. tropicalis strain BPU1 on a specially designed medium, which would open up elaborate research on this yeast. Copyright

Pseudomonas sp. BUP6, a novel isolate from Malabari goat produces an efficient rhamnolipid type biosurfactant.

This study describes the characteristics of a biosurfactant produced by Pseudomonas sp. BUP6, a rumen bacterium, and optimization of parameters required for its production. Initial screening of five parameters (pH, temperature, agitation, incubation, and substrate concentration) was carried out employing Plackett–Burman design, which reduced the number of parameters to 3 (pH, temperature, and incubation) according to their significance on the yield of biosurfactant. A suitable statistical model for the production of biosurfactant by Pseudomonas sp. BUP6 was established according to Box–Behnken design, which resulted in 11% increase (at pH 7, 35 °C, incubation 75 h) in the yield (2070 mg L−1) of biosurfactant. The biosurfactant was found stable at a wide range of pH (3–9) with 48 mg L−1 critical micelle concentration; and maintained over 90% of its emulsification ability even after boiling and in presence of sodium chloride (0.5%). The highest cell hydrophobicity (37%) and emulsification (69%) indices were determined with groundnut oil and kerosene, respectively. The biosurfactant was found to inhibit the growth and adhesion of E. coli and S. aureus significantly. From the phytotoxicity studies, the biosurfactant did not show any adverse effect on the germinating seeds of rice and green gram. The structural characterization of biosurfactant employing orcinol method, thin layer chromatography and FT‐IR indicated that it is a rhamnolipid (glycolipid). Thus, Pseudomonas sp. BUP6, a novel isolate from Malabari goat is demonstrated as a producer of an efficient rhamnolipid type biosurfactant suitable for application in various industries.

New Bacillus thuringiensis strain isolated from the gut of Malabari goat is effective against Tetranychus macfarlanei

This study illustrates a novel strain (designated as BPU5) of Bacillus thuringiensis (Bt) isolated from the rumen of Malabari goat, capable of producing polymorphic δ‐endotoxin crystals concomitantly with sporulation in Luria–Bertani medium (LB), and the δ‐endotoxin was efficient to combat Tetranychus macfarlanei, a devastating mite. Polymorphic δ‐endotoxin crystals produced were assessed by scanning electron microscopy and monitored its production concomitantly with sporulation in LB with or without sugar supplements. Toxicity of the δ‐endotoxin was assessed on T. macfarlanei using leaf disc bioassay method. Mortality rate was determined by comparing the survival of mites on the diet (prepared in 10% sucrose and powdered rice husk) containing different concentrations (1–10 mg/ml) of 72‐h‐old crude pellet (dried mixture of δ‐endotoxin (17 mg/g pellet), endospores and a few vegetative cells) or control diet with autoclaved pellet. The maximum production (1.39 mg/ml) of δ‐endotoxin was observed at 72 h in LB. Among the sugars (glucose, sucrose, maltose or lactose) tested as additional carbon source, glucose (8 g/l) enhanced (1.82 mg/ml) the production of δ‐endotoxin by 30%. The lethal concentration (LC50) required to kill 50% mites was estimated as 8.024 mg/ml. The δ‐endotoxin produced by B. thuringiensis BPU5 is shown to efficiently combat T. macfarlanei, a devastating mite infesting agricultural fields.

Pseudomonas aeruginosa strain BUP2, a novel bacterium inhabiting the rumen of Malabari goat, produces an efficient lipase

Abstract Pseudomonas aeruginosa strain BUP2 (MTCC No. 5924), a novel bacterium isolated from the rumen of the Malabari goat was explored in this study for its efficiency in the production of lipase in Benjamin Unni Priji medium supplemented with 1% groundnut oil. Plackett-Burman and Box-Behnken designs were applied for optimizing the culture parameters statistically for the enhanced production of lipase; and temperature (28°C), pH (6) and incubation time (24 h) were found as significant factors for increasing the production of lipase by 11% (from 152 to 171 U/mL). Using (NH4)2SO4 fractionation and Sephadex G-100 gel filtration techniques, the lipase was purified to homogeneity (36 folds with 20% yield) with 2,392 U/mg specific activity; its apparent MW was 29 kDa, as judged by SDS-PAGE. The maximum activity (2,802 U/mL and 177% specific activity) of the purified lipase was observed with 50 mM para-nitrophenyl palmitate as substrate (at pH 8, 45°C temperature, 5.0 mM Ca2+ and 0.5% Triton X-100, after 30 min of incubation). The Km and Vmax values of the purified lipase were found as 4.75 mM and 999 μmol/min/mg, respectively; and that this may be the first report on a lipase produced by a microorganism inhabiting the rumen of a goat. Briefly, the alkalophilic and thermotolerant lipase produced by P. aeruginosa strain BUP2 with higher specific activity would find better utility in detergency; moreover, this low MW protein is a good candidate for genetic engineering toward catalytic resolution of fine chemicals.

Bioplastics: Advances in Polyhydroxybutyrate Research

After giving a glimpse into the global market of bioplastics and briefly describing the various forms of bioplastics, this chapter presents a detailed discussion on polyhydroxybutyrate (PHB), the predominant polyhydroxyalkanoate produced by bacteria as stored food. This review encompasses interdependent sections on the organization of the PHB granules, their physical properties, factors affecting production, producing bacteria, genetic basis of production, overproduction using recombinant techniques, metabolic pathways, blends, general applications, degradation and conclusions. To sum up, a collective and global initiative of scientists, law makers and entrepreneurs is required to enhance the present market share of bioplastics from a mere 1% to a state where bioplastics replace petroplastics completely in the near future. However, considering the small share of PHB in total bioplastics, and its unique characteristics, it is advisable that PHB research should focus on developing biomedical devices for tissue and organ engineering; cosmetics and health products; food packaging materials; and delivery systems for the controlled release of drugs, fertilizers and pesticides.