C. R. Soccol

Review advances in microbial amylases.

This review makes a comprehensive survey of microbial amylases, i.e. alpha-amylase, beta-amylase and glucoamylase. Amylases are among the most important enzymes and are of great significance in present-day biotechnology. Although they can be derived from several sources, such as plants, animals and micro-organisms, the enzymes from microbial sources generally meet industrial demands. Microbial amylases could be potentially useful in the pharmaceutical and fine-chemical industries if enzymes with suitable properties could be prepared. With the advent of new frontiers in biotechnology, the spectrum of amylase application has widened in many other fields, such as clinical, medicinal and analytical chemistries, as well as their widespread application in starch saccharification and in the textile, food, brewing and distilling industries. In this review, after a brief description of the sources of amylases, we discuss the molecular biology of amylases, describing structures, cloning, sequences, and protoplast fusion and mutagenesis. This is followed by sections on their production and finally the properties of various amylases.

Kinetics of Gibberella fujikuroi Growth and Gibberellic Acid Production by Solid-State Fermentation in a Packed-Bed Column Bioreactor

In this work the growth of Gibberella fujikuroi and gibberellic acid (GA3) production were studied using coffee husk and cassava bagasse as substrates in a packed‐bed column bioreactor connected to a gas chromatograph for exit gas analysis. With the respirometric data, a logarithmic correlation between accumulated CO2 and biomass production was determined, and the kinetics of the fungal growth was compared for estimated and experimental data. The solid medium consisted of coffee husk (pretreated with alkali solution), mixed with cassava bagasse (7:3 dry weight basis), with a substrate initial pH of 5.2 and moisture of 77%. Cultivation was carried out in glass columns, which were packed with preinoculated substrate and with forced aeration of 0.24 L of air/[h (g of substrate)] for the first 3 days, and 0.72 L of air/[h (g of substrate)] for the remaining period. The maximum specific growth rate (μm) obtained was 0.052 h−1 (between 24 and 48 h of fermentation). A production of 0.925 g of GA3/kg of substrate was achieved after 6 days of fermentation.

Efficient genetic transformation and regeneration system from hairy root of Origanum vulgare.

Origanum vulgare L is commonly known as a wild marjoram and winter sweet which has been used in the traditional medicine due to its therapeutic effects as stimulant, anticancer, antioxidant, antibacterial, anti-inflammatory and many other diseases. A reliable gene transfer system via Agrobacterium rhizogenes and plant regeneration via hairy roots was established in O. vulgare for the first time. The frequency of induced hairy roots was different by modification of the co-cultivation medium elements after infection by Agrobacterium rhizogenes strains K599 and ATCC15834. High transformation frequency (91.3xa0%) was achieved by co-cultivation of explants with A. rhizogenes on modified (MS) medium. The frequency of calli induction with an 81.5xa0% was achieved from hairy roots on MS medium with 0.25xa0mg/L−1 2,4-D. For shoot induction, initiated calli was transferred into a medium containing various concentrations of BA (0.1, 0.25, 0.5, 0.75 and 1xa0mg/L−1). The frequency of shoot generation (85.18xa0%) was achieved in medium fortified with 0.25xa0mg/L−1 of BA. Shoots were placed on MS medium with 0.25xa0mg/l IBA for root induction. Roots appeared and induction rate was achieved after 15xa0days.