The potential of bioflocculant-producing bacteria as inoculum for biofloc based systems

Aim: Biological flocculants has been widely used around the world to replace the usage of synthetic flocculants for wastewater treatment.Anew green technology using biological flocculant known as biofloc system was developed which offers zero water exchanged, low feed conversion ratio (FCR) and high nutritional profile. This study was conducted to determine the most potential bioflocculant-producing bacteria isolated from biofloc sampleinPacific Whiteleg shrimp,P. vannameiculture pond. Methodology: Biofloc sample was collected using Imhoff cone and bacteria was isolated. The most abundant bacteria isolated throughout P. vannamei culture period was selected for screening of bioflocculant-producing bacteria usingYPG medium and flocculation activity using floc-jar test. Results: Screening of bioflocculant-producing bacteria showed that B. infantis, N. aquimarinus, B. cereus, H. venusta, Pseudoalteromonas sp., and B. safensis were characterized as highly mucoid and ropy colony morpologies. The highest flocculation activity with 93% was showed by B. infantis followed by N. aquimarinus (91%), B. cereus (87%), H. venusta (79%), Pseudoalteromonas (78%), while the lowest flocculation activity was showed byB. safensiswith 69%. Interpretation: As bacteria grew, extracellular polymeric substances (EPS) produced were involved in flocculation process. Each bacteria produced different EPS composition which differed their ability in flocculation process. Therefore, bacteria with high flocculation activity are potentially used as inoculum to increase flocculation processinbiofloc production

Effect of different aeration units, nitrogen types and inoculum on biofloc formation for improvement of Pacific Whiteleg shrimp production

Biofloc formation is affected by the addition of carbon sources and the adequate aeration supply with a proper arrangement of aeration units. Apart from molasses was commonly used as carbon sources, the effect of different nitrogen types was also critically important in the biofloc formation. This study aimed to evaluate the effect of different aeration units and nitrogen types on the biofloc formation using bioflocculant-producing bacteria as inoculum. Experimental set-up was prepared with two types of aeration units (i.e.: air stone and aerotube) and three nitrogen types (i.e.: fish meal, grounded pellet and pellet). Water quality parameters, water physical appearance, biofloc volume and shrimp biomass were observed within 30 days of the study period. There were no significant difference (P ≤ 0.05) between the water quality parameters, however, biofloc volume and shrimp biomass showed a significant difference with the aeration units. Nitrogen types using pellet showed positive results with the formation of biofloc, while there was no formation of biofloc in the other treatments. Consequently, injection of bioflocculant-producing bacteria for the rapid formation of biofloc was recommended with a proper installation of aerotube units and pellet as a nitrogen type