PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Seaweed processing into juice extraction produces a large volume by product which from a kilo of seaweed (Kappaphycus alverezii), 800 grams (80%) of residue goes to waste after the extraction. The aim of this study was to improve the growth and yield of lettuce as: height, growth rate, leaf length, above and below ground fresh weight through the use of Fermented Marine Macro Algae Residue. Four treatments were compared; solid seaweed sludge (by-product of fermentation at 10tons/ha), fermented liquid seaweed (10ml/L) and the combination of both against a commercially available seaweed-based fertilizer (10ml/L). For lettuce (Lactuca sativa var. Curly Green) plant height after five days from transplanting showed that application of seaweed sludge (solid seaweed fertilizer) outperformed the commercial fertilizer at 10.01±0.72SE cm and 6.28 ±0.0.57SE cm respectively. On the 20^th day, the combination of both liquid and solid seaweed fertilizer produced the tallest plants (plant height) with the longest leaves at 13.87±0.42SE cm and 15.43±0.54SE cm, respectively. The fastest growth rate was achieved from 16-20 days with the combined application of liquid and solid seaweed fertilizer at 5.31±0.44SE cm. From transplanting (0-5 days), highest growth rate was achieved by applying solid seaweed fertilizer alone (4.08±0.44SE cm/5-days). At comparable below ground weight, liquid fertilizer application resulted to almost three times heavier above ground weight (270.17±163.61SE g/plant) than all of the treatments. Thus, waste products from processing seaweed-based beverage can effectively be utilized as fertilizer through fermentation in both liquid and in solid form, and more importantly in combination for the production of lettuce.