Seasonal occurences of epiphytes and their effects on the quality of carrageenan in commercially cultivated Kappaphycus Alvarezii.

Sabah is the only state in Malaysia with a successful seaweed cultivation programme. Malaysia is the third largest producer of Kappaphycus and Eucheuma in the world with an annual harvest of 6,500 tonnes. The seaweed industry faces various problems in cultivation especially from bacterial causing disease such as "ice-ice" disease and from epiphyte infection. Epiphyte infection of crops has been a long standing problem but very little has been studied on it. This research sets out to look into the characteristics of the epiphytes as well as to study the effects of the epiphytes on the seaweed as well as on the quality of the carrageenan produced. Taxonomical identification has found that the infecting epiphyte to be Neosiphonia apiculata. This is concurrent with species found on samples obtained from outbreaks in the Philippines and Tanzania, with all three outbreaks displaying similar symptoms. It was also found that the epiphytes caused massive damage to the infected thalli causing crop loss and degradation; including cortical swellings, pit formation, deformities of the seaweed surface and large growth of epiphytes. The pattern in outbreak showed that the epiphytes are seasonal in Malaysia, reaching peak growth between the months of April to June and August to October, whereby 90% of the K. alvarezii were covered with hair like protrusions measuring 0.4 - 5.0 cm. Nutritional testing carried out showed seasonal trend in nutritional properties, farm locations and with the onset of epiphyte infection. Testing was carried out on moisture, ash content, phenolics, lipid, carrageenan yield and fatty acids, showed significant differences. Nutritional values ranged between 90 - 93% for moisture, 40 - 50% for ash, 4 - 7 % for protein, 0.04 - 0.15% lipid, 20 - 120 ng/g total fatty acids, 0.1 - 0.7 mg/g phenolic content and 30 - 75% carrageenan yield. Rheological properties also showed decrease in properties such as carrageenan yield, melting point, viscosity and gel strength for carrageenan extracted from epiphyte infected seaweed. Molecular studies showed that the epiphyte infected carrageenan showed no structural change but the molecular weight was 80 KD as compared to 800 KD of the healthy carageenan.