Growth of Aspergillus niger and glucoamylase production correlated well with the water activity of the substrate (wheat bran plus corn flour) in a solid-state fermentation. Both were maximal at an initial water activity of 0.936. Glycoamylase reached 550 units/g dry substrate after 96 h.
Amylases are one of the main enzymes used in various industries such as food, fermentation, textile, and pharmaceuticals. Microorganisms are the potent sources of amylase enzyme, apart from plant and animal sources. Fungal amylases are more stable than bacterial amylases. The production of extracellular α‐amylase from Aspergillus tamarii MTCC5152 using solid‐state and submerged fermentation (SSF and SmF) and the various nutritional factors influencing its production were studied. A higher activity of α‐amylase (519.40 u/g) was attained in a medium having wheat bran (WB) alone as the substrate at an initial moisture content of 70% (v/w) with 2.5% (v/w) of inoculum level (containing 106 spores/ml) after 4 days of incubation at 28°C by SSF. Addition of 1% glucose to WB containing basal medium enhanced α‐amylase production (6.49 u/ml) after 4 days of incubation by SmF method. Comparative evaluation of enzyme production by SSF and SmF methods produced better results in SSF method.
Cell immobilization is one of the common techniques for increasing the overall cell concentration and productivity. Bacillus amyloliquefaciens MBL27 cells were immobilized in calcium alginate beads and it is a promising method for repeated AMP (antimicrobial protein) production. The present study aimed at determining the optimal conditions for immobilization of B. amyloliquefaciens MBL27 cells in calcium alginate beads and the operational stability for enhanced production of the AMP. AMP production with free and immobilized cells was also done. In batch fermentation, maximum AMP production (7300 AU (arbitrary units)/ml against Staphylococcus aureus) was obtained with immobilized cells in shake flasks under optimized parameters such as 3% (w/v) sodium alginate, 136 mM CaCl2 with 350 alginate beads/flask of 2.7-3.0 mm diameter. In repeated cultivation, the highest activity was obtained after the second cycle of use and approx. 94% production was noted up to the fifth cycle. The immobilized cells of B. amyloliquefaciens MBL27 in alginate beads are more efficient for the production of AMP and had good stability. The potential application of AMP as a wound healant and the need for development of economical methods for improved production make whole cell immobilization an excellent alternative method for enhanced AMP production.
Recently, the requirement for various real-time applications over Mobile ad-hoc networks (MANETs) has been increasing tremandously. Packet scheduling and routing algorithms are the important factors for improving the Quality of service (QoS) parameters over the MANETs. Still, it is not easy to proficiently aid multimedia broadcast with its stringent delay constraints over MANETs. Moreover, there are several problems in assisting QoS over MANETs owing to interference amid nodes in the network. In this paper, Minimum Length Minimum Delay Scheduling (MLMDS) using Artificial Butterfly Optimization (ABO) algorithm is proposed. A fitness function for ABO is derived in terms of the round trip scheduling delay, the conflict graph and the amount of slots in the data sub-frame. A slot selection algorithm is proposed such that the selected slot is supposed to yield lesser delay and spatial reuse. By simulation results, it has been shown that MLMDS achieves minimum delay with higher throughput.
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