Santilata Sahoo

Micropropagation of Zingiber rubens and assessment of genetic stability through RAPD and ISSR markers

Protocol was developed for high frequency in vitro multiplication of an endemic species, Zingiber rubens Roxb. The sprouted buds of the rhizomes were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA; 0.5–5.0 mg dm−3), indole-3-acetic acid (IAA; 0.5–2.0 mg dm−3), kinetin (KIN; 1.0–3.0 mg dm−3), naphthaleneacetic acid (NAA; 0.5–1.0 mg dm−3) and adenine sulphate (ADS; 80–100 mg dm−3). MS basal medium supplemented with 3 mg dm−3 BA and 0.5 mg dm−3 IAA was optimum for shoot elongation. The elongated shoots (1–2 cm) were transferred to multiplication medium containing 2 mg dm−3 BA, 1 mg dm−3 IAA and 100 mg dm−3 ADS. The multiplication rate remained unchanged in subsequent subcultures. Upon ex vitro transfer, 85 % of plants survived. Genetic stability of micropropagated clones were periodically evaluated at an interval of 6 months up to 30 months in culture using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analysis and genetic uniformity in all regenerants was confirmed.

Characterization of biotechnologically relevant extracellular lipase produced by Aspergillus terreus NCFT 4269.10

Enzyme production by Aspergillus terreus NCFT 4269.10 was studied under liquid static surface and solid-state fermentation using mustard oil cake as a substrate. The maximum lipase biosynthesis was observed after incubation at 30 °C for 96 h. Among the domestic oils tested, the maximum lipase biosynthesis was achieved using palm oil. The crude lipase was purified 2.56-fold to electrophoretic homogeneity, with a yield of 8.44%, and the protein had a molecular weight of 46.3 kDa as determined by SDS-PAGE. Enzyme characterization confirmed that the purified lipase was most active at pH 6.0, temperature of 50 °C, and substrate concentration of 1.5%. The enzyme was thermostable at 60 °C for 1 h, and the optimum enzyme–substrate reaction time was 30 min. Sodium dodecyl sulfate and commercial detergents did not significantly affect lipase activity during 30-min incubation at 30 °C. Among the metal ions tested, the maximum lipase activity was attained in the presence of Zn2+, followed by Mg2+ and Fe2+. Lipase activity was not significantly affected in the presence of ethylenediaminetetraacetic acid, sodium lauryl sulfate and Triton X-100. Phenylmethylsulfonyl fluoride (1 mM) and the reducing, β-mercaptoethanol significantly inhibited lipase activity. The remarkable stability in the presence of detergents, additives, inhibitors and metal ions makes this lipase unique and a potential candidate for significant biotechnological exploitation.

Characterization of purified α-amylase produced by Aspergillus terreus NCFT 4269.10 using pearl millet as substrate

Abstract α-amylase was produced by Aspergillus terreus NCFT 4269.10 using both liquid static surface (LSSF) and solid-state fermentation using pearl millet residues as substrate. The maximum production of α-amylase was noticed at 30°C incubated for 96h. The crude α-amylase was purified to electrophoretic homogeneity and characterized. Characterization of amylase confirmed that the purified α-amylase was found to be most stable at pH 5.0, 60°C temperature, and a substrate concentration of 1.25%. The enzyme was active for 40 min at 70°C with an optimum enzyme–substrate reaction time of 60 min. Amylase was compatible with all detergents tested having highest activity with Surf excel followed by Henko and Ariel. SDS and Tween 20 reduced the activity. Among the metal ions tested, the maximum α-amylase activity was attained in the presence of Ca2+, followed by Mg2+ and Mn2+. The activity of α-amylase was not considerably affected in the presence of ethylenediaminetetraacetic acid and Triton X-100. Amylase activity was accelerated in the presence of sodium lauryl sulfate and phenylmethylsulfonyl fluoride did not significantly (or slightly) affect the activity and stability. Tween 20, urea (5%), and the reducing agent, β-mercaptoethanol significantly inhibited the activity of α-amylase. Owing to its noteworthy stability in the presence of detergents, additives, inhibitors, and metal ions, this α-amylase could be an impending enzyme for significant industrial exploitations.