Browsing by Author "Helena Khatoon"

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    Biofloc as a potential natural feed for shrimp postlarvae
    (International Biodeterioration and Biodegradation, 2016) Helena Khatoon; Sanjoy Banerjee; Gregory Tan Guan Yuan; Noorazilah Haris; Mhd Ikhwanuddin; Mohd Azmi Ambak; Azizah Endut
    In this study, the suitability of excess biofloc that was discarded as waste from Litopenaeus vannamei farm effluent was investigated for effectiveness as a dietary replacement in rearing L. vannamei postlarvae (PL). A commercial shrimp diet (control) was compared to four diets containing dried waste biofloc at 25%, 50%, 75% and 100% replacement levels and fed to shrimp PL to evaluate the survival rate, growth performance and nutritional composition. Total ammonium nitrogen and nitrite nitrogen were maintained in culture tanks with minimal water exchange throughout the experiment. Results showed that PLs fed with 50% biofloc feed (50% BF) had significantly higher (p < 0.05) specific growth rate compared to the other treatments. In addition, PLs fed with 50% and 75% BF had significantly higher survival rate (p < 0.05) compared to those fed with commercial feed only. However, protein content of PLs fed with 50% and 75% BF was comparable to those of 100% commercial feed. This study demonstrates that waste biofloc has potential to be used as a cost effective feed for rearing shrimp PLs.
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    Phytoplankton Ankistrodesmus sp. as an alternative tool in controlling fish disease
    (AACL Bioflux, 2016-02-04) Noor E. Sharifah; Mohamad Z. M. Nosi; Helena Khatoon
    The ability of the freshwater phytoplankton, Ankistrodesmus sp. to inhibit the growth of the fish pathogenic bacterial, Aeromonas hydrophila and Streptococcus agalactiae was tested. The inhibitory activity of Ankistrodesmus sp. against these bacterial were observed in (1) phytoplankton culturing control medium, Bold Basal Medium (BBM) and (2) filtrate prepared from Ankistrodesmus sp. cultured in BBM. The cell densities of A. hydrophila when cultured in Ankistrodesmus sp. filtrate medium showed no significant difference (P>0.05) from those cultured in control medium. In contrast, there was inhibition activity on the growth of S. agalactiae observed in Ankistrodesmus sp. filtrate medium against those cultured in control medium. The cell density of S. agalactiae was significantly lower (P<0.05) in Ankistrodesmus sp. filtrate medium compared to the control medium started from day 4th until the 14th day. Thus, the present study concluded that Ankistrodesmus sp. can be an essential tool for inhibiting the growth of S. agalactiae
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    A study of coagulating protein of Moringa oleifera in microalgae bioflocculation
    (International Biodeterioration and Biodegradation, 2016) Siti Hajar Abdul Hamid; Fathurrahman Lananan; Helena Khatoon; Ahmad Jusoh; Azizah Endut
    Moringa oleifera is characterized by high coagulation properties, low cost and low toxicity hence is very promising to be utilized as an alternative coagulant to recover microalgae biomass from its suspension system. Hence, this study was performed with the objective to investigate the potentiality of M. oleifera as coagulant agent in harvesting microalgae and to investigate the effect of zeta potential in its coagulation-flocculation activity. Bradford protein assay was applied for rapid and accurate determination of protein concentration in the M. oleifera seed powder and protein powder. The flocculation activities were determined at isoelectric pH by computing the flocculation efficiency in terms of microalgae biomass recovery and removal percentage at various coagulant dosages. It was observed that the protein concentration was 211.71 mg g 1 mL 1 in M. oleifera seed powder and 188.16 mg g 1 mL 1 in protein powder which yielded 97% and 78% of biomass recovery, respectively at the dosage of 10 mg L 1. Result showed that M. oleifera seed derivatives supersede chemical coagulant, alum which yielded 34% of biomass recovery at the same dosage. M. oleifera seed powder and protein powder was proven to be highly promising bio-coagulant and suitable alternative to the chemical coagulant in environmentallysustainable harvesting of microalgae biomass.