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

Abstract

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.