1.1 BACKGROUND OF THE STUDY
Macroalgae are members of the huge group of aquatic plants that known as algae. The algae are primitive photosynthetic plants that include the single celled phytoplankton of the multi-celled macroalgae, or seaweeds, that can range in size from microscopic to the giant kelps (Macrocystis) (Millar, 2011).
Red, green, and brown seaweed produce large quantities of polysaccharides such as fucoidan, alginic acid, fucoidan, agar, cellulose, laminarin and carrageenan. Alginate is one of the main organic components in seaweed, and is as high as 50% in brown algal species such as wakame (Undaria pinnatifida) (Skriptsova et al. 2004). These polysaccharides have a variety of applications including antioxidants (de Souza et al. 2007), antitumor agents (Fukahori et al. 2008), anticoagulants (Li et al. 2008), anti-inflammatory agents, cosmetics, food ingredients, industrial products (Dhargalkar and Pereira 2005), and production of biofuel (Hom et al. 2000). In 2016, the global production of aquatic plants, mostly seaweeds, reached 31.2 million tonnes, 96.5 % (30.1 million tonnes) of which was harvested from aquaculture (FAO 2018). Regarding increasing seaweed products, there has been an increase in the quantities of seaweed wastes that are produced by industries (Fei et al. 1999); for example, in Japan more than 200,000 tonnes of Wakame (Undaria pinnatifida) is produced every year (Fujii and Korenage 2000). Another reasons in recent increased of seaweed waste is the eutrophication of coastal seawater resulting in a rapid increased in seaweeds growth and increased in drifting seaweeds (Tang et al., 2008). Furthermore, because most of this seaweed waste is confined in landfills or incinerated, the ability to either use or reduce the quantities of this harvested seaweed waste is receiving increased attention around the globe.
For preservation of the marine environment and recycling of organic substances, the utilization and the disposal are very important. However due to its complicated molecular structure, it is not easy for the general microorganisms to degrade the alginate contents in the seaweed. Thus it is important to find the effective way for disposal of seaweed wastes by seaweed polysaccharide like alginate degrading bacteria. The aim of this research is to isolate and characterize the seaweed degrading bacteria from marine herbivore animal gut and brown algae. In this research, isolation of the bacterium with seaweed degradability will be utilized for the future references for seaweed wastes disposal.
1.2 PROBLEM STATEMENT
In the recent years, the increasing amount of the seaweed wastes were due to two main reasons; one is the increasing amount of industries that culturing the seaweeds as the industrials resources and another is the eutrophication of seawater which plays role in resulting in rapid growth of the seaweeds (Skriptsova et al. 2004).
In addition, while the increasing amount of seaweed wastes is continuously arising, the utilization of the seaweed wastes is still insufficient. There is only few ways for seaweed waste utilization that has been recognized globally though the research such as tumour inhibitor, anticoagulants, therapeutic agents and biofuel (Nayar and Bott, 2014).
Also the data that accounts for the seaweed degrading bacteria from the sample such as Holothuria atra and Padina australis still insufficient till the dates. However, there’s still lot of other research has been done for the seaweed degrading bacteria from the various samples. For example, the bacteria samples from the sea cucumber, sea urchin, rabbit fish and surfaces of the seaweeds. Thus, the aim of this study is to……………..
1.3 SIGNIFICANCE OF THE STUDY
The finding of this study will provide the database on seaweed degrading bacteria from the bacterial isolates from the black sea cucumber (Holothuria atra) and brown seaweed (Padina australis) and their degradability characteristics. The finding from this study also can be used as a reference in utilization of the seaweed wastes for better use. With the better and sufficient choices of seaweed wastes utilization, it will also contribute to minimize the increasing of seaweed waste every year.
1.4 OBJECTIVES OF THE STUDY
The aim of this study is to embark the following objectives:
1. Isolation of degrading bacteria from the gut of Holothuria atra and surface of Padina australis.
2. Observing the degradability of seaweeds polysaccharides by each bacterial isolate.