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House of industrially important bioactive metabolites: A review on actinobacteria

Tue, 01 Oct 2019 00:00:00 GMT

Title: House of industrially important bioactive metabolites: A review on actinobacteria Authors: Bano, Naushin; Siddiqui, Saba; Amir, Mohammad; Roohi Abstract: The actinomycetes are Gram-positive bacteria present in natural habitats, most profoundly in soil, freshwater, sea water and composts. Actinomycetes have high GC (guanine-cytosine) content and characterized by a complex life cycle. The morphology of actinomycetes looks like fungi and the reproduction takes place either by hyphae fragmentation or by spore production in the mycelium. Actinomycetes serves as a large pool for secondary metabolites production with potent biological activities and therapeutic properties like antifungal, antibiotics, enzymatic, plant growth promoting rhizobacteria (PGPR), in xenobiotics and bioremediation. These bioactive metabolites production can be enhanced using high-throughput fermentation and by combinatorial biosynthesis during optimization. Present research should be focused on the potential of less explored actinomycetes from extreme environments that can be utilized as sustainable herald for green biotechnology. In this review, habitat, life cycle and production optimization of actinomycetes in selective media are explained but article is emphasized on biotechnological potential of actinomycetes that are relevant for industries, agriculture and allied sectors. Page(s): 293-304

Physicochemical properties of free and calcium alginate immobilized alkaline pectin lyase from Bacillus cereus

Tue, 01 Oct 2019 00:00:00 GMT

Title: Physicochemical properties of free and calcium alginate immobilized alkaline pectin lyase from Bacillus cereus Authors: Kohli, Pooja; Mehta, Akshita; Singh, Ashwant; Gupta, Reena Abstract: Purified pectin lyase from Bacillus cereus was successfully immobilized in alginate beads with a high binding efficiency of 84.55%. The optimal immobilization was achieved using 2.5% (w/v) alginate concentration. Both free and immobilized enzyme showed optimum pH of 10.0 and temperatures of 40 and 45°C respectively. Pectin lyase gave maximum activity at a substrate concentration of 0.5% w/v for free and 0.75% w/v for the immobilized enzyme and relatively similar V_max values were obtained for both free (3.3 µmol/min) and immobilized pectin lyase (3.6 µmol/min). The K_mfor the immobilized pectin lyase (0.19 mg/ml) was slightly higher than that of the free (0.16 mg/ml) enzyme. The maximum inhibition of 50.2% was observed in the presence of Hg²⁺ion for free pectin lyase and immobilized enzyme showed maximum inhibition of 67.32% in the presence of Na⁺ ion with statistically significant p-value (p < 0.05). Thermal stability was not significantly altered by immobilization. Thermal stability of free and immobilized pectin lyase was relatively similar at different temperatures. The immobilized pectin lyase retained almost 53% of its original activity up to 7^th cycle. Furthermore, during storage at 4°C, immobilized pectin lyase retained relative activity of 79.77% and free enzyme retained 63.63% relative activity upto 35 days of storage, this indicated that the immobilization improved stability of the enzyme. Page(s): 305-314

Quantification of classical swine fever virus load by one-step TaqMan real-time RT-PCR assay

Tue, 01 Oct 2019 00:00:00 GMT

Title: Quantification of classical swine fever virus load by one-step TaqMan real-time RT-PCR assay Authors: Rajbongshi, Gitika; Barman, Nagendra Nath; Das, S. K.; Khatoon, Elina Abstract: A fluorogenic-probe hydrolysis (TaqMan) real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay based on amplification of a 93 bp fragment from 5’un-translated region (5’UTR) of classical swine fever virus was used for detection and absolute quantification of the virus in clinical and tissue samples. For determining analytical sensitivity, an in vitro transcript RNA containing 5’UTR of classical swine fever virus (CSFV) strain Alfort187 from plasmid pCRXLV324-6 was used as a positive control and a standard for quantification of CSFV genomic RNA copies. The real-time quantitative RT-PCR (qRT-PCR) assay was used to assess the CSFV shedding from naturally infected pigs in whole blood, nasal swab and also in tissue samples. Used qRT-PCR was specific and sensitive as it could detect as low as 16.3 copies of CSFV genomic RNA. The assay was also reproducible as shown by satisfactory low intra-assay (0.80 % to 1.87 %) and inter-assay (1.00% to 3.80%) coefficient of variation with an efficiency of 102.3% and R² of 0.993. Thus, the real-time qRT-PCR assay described here allows rapid, specific and sensitive laboratory detection and quantification of CSFV genomic RNA copies. Page(s): 315-322

Salinity mediated enhancement in protein and pigment content in Spirulina (Arthrospira) platensis

Tue, 01 Oct 2019 00:00:00 GMT

Title: Salinity mediated enhancement in protein and pigment content in Spirulina (Arthrospira) platensis Authors: Prabhath, G P W A; Shukla, S P; Kumar, K; Nuwansi, K K T Abstract: Spirulina (Arthrospira) platensis a filamentous multi cellular cyanobacterium utilized as animal feed and human food supplement. This cyanobacterium is also a rich source of value-added pigments with diverse applications in the food industry, pharmaceuticals and molecular biology. This report describes a procedure for enhancement of the yield of value-added pigment; c-phycocyanin (CPC) through the manipulation of salinity of the medium. The increase in salinity (sodium chloride-NaCl) from 0 to 3 g l^-1 of the prescribed growth medium resulted in a considerable increase (11.83%) in CPC content. Growth of the organism and the purity of the CPC were not affected at elevated salt concentration. However, a further increase in the salinity (NaCl) from 3 to 7 g l^-1 resulted in a decline in the content (26.67%) and purity (31.13%) of CPC. Considering the enhanced growth and CPC content through the manipulation of the concentration of the salt NaCl in the medium, it is concluded that a moderate amount of the salt (3 g l^-1NaCl) in the medium is a feasible and cost-effective approach for obtaining elevated protein biomass and enhanced the yield of the value-added pigment CCPS. Page(s): 323-329