A research was conducted to increase the virulence of Beauvaria bassiana to the rice bug, L. acuta, by adding four different substances (materials) to the rice media to grow the fungus. The research was conducted from April to August 2011 at Polinela Laboratory, Bandar Lampung. To do this a set of experimental unit consisting of five treatments and five replications were arranged in completely randomized design. The four treatments were media made up of rice (rice based media) each given or added with four different materials such as rice skin powder, corn sugar, grasshopper powder and chitosan powder. The result showed that B. bassiana grown on rice media added with grasshopper powder or rice skin powder were able of causing mortality to the L. acuta as high as 78% and 71%, respectively, meaning that both mortalities were much higher than that of other replication. The virulence values of Beauveria bassiana grown on those both powder were also higher than that of three others.
Carrageenan is a hydrocolloid compound from Rhodophyceae extraction of K. alvarezii using alkali solvents. Conventional extraction methods that have been using certain solvents in large volumes require a long time and low yields resulting in high production costs and large amounts of waste which pollute the environment. These adverse effects can be minimized by extraction with the help of ultrasonic waves which will provide an intensive stirring effect to damage the cell walls of seaweed so that the process of mass transfer will be faster. The extraction temperature greatly influences the quantity and quality of carrageenan which is often carried out in conventional extraction. In carrageenan extraction activities from K. alvarezii with the help of ultrasonic waves, the effects of temperature and time on these two parameters will also be studied. This activity was conducted to determine the time and temperature of carrageenan extraction from K. alvarezii seaweed using an ultrasonic frequency of 40 kHz with temperature variations of 30, 40, 50, 60, and 70 °C, and time variations of 20, 25, 30, 35 and 40 minutes. The results of extraction of K.alvarezii seaweed with a time variation of 40 minutes and temperature variation is 70 °C, with the optimum value of temperature and extraction time is 70 °C for 30 minutes which produces carrageenan as much as 44.46%. The carrageenan quality test produced water content ranging from 6.27-14.18%, ash content 12.33-13.69%, viscosity of 10.4-27.9 cP and gel strength ranged from 926.26 to 4945.99 dyne / cm2.
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