Immobilized microbial consortia: An eco-friendly and sustainable solution for aquaculture waste management

Abstract

Aquaculture pond is a dynamic ecosystem with continuously changing physical, chemical, and biological elements. Environmental issues often create significant hindrances to long-term development of aquaculture industries in developing countries. Lack of knowledge on scientific aquaculture farm management has resulted in excessive usage of antibiotics and other chemicals leading to significant impacts to the surrounding ecosystem. While focussing on sustainable aquaculture, pond bottom sediment quality is an important aspect in aquaculture; but it receives far less attention than water quality. Usually, deterioration of accumulated organic matter in bottom sediment increases oxygen demand and influences redox potential. This creates anoxic conditions in the sediments and at the sediment-water interface, and releases ammonia, hydrogen sulfide, nitrogenous compounds and other toxic gases, leading to massive losses in aquaculture production. This could therefore reduce production capacity and be less profitable to farmers, discouraging them from entering to aquaculture sectors, especially the younger generation. An eco-friendly, convenient and low-cost aquaculture waste management strategies need to be adopted to mitigate these issues and make the system productive and profitable. This review critically evaluates the importance, feasibility and bioremediation potential of Immobilized microbial consortia (IMC) in general and specifically addresses Bacillus MCCB 101 for detritus or organic matter degradation, nitrifying bacterial consortia (NBC) for nitrification and photosynthetic sulfur bacteria (PSB), Rhodospeudomonas julia MCCB 147, for hydrogen sulfide mitigation from aquaculture ponds towards converting to a long-term sustainable production system.

Keywords

• Immobilization
• Organic waste accumulation
• Sediment oxygen demand
• Redox potential
• Anaerobic condition
• Mortality