Microbial reclamation of squid pens and shrimp shells

Abstract

Byproducts generated in high levels by marine processes have been recognized for their value as recyclable or reclaimable waste. Among marine byproducts, shrimp shells, crab shells, and squid pens have the highest chitin content. The chemical treatments of these chitin-containing byproducts for preparing chitin and chitosan create waste disposal problems because neutralization and detoxification of the discharged wastewater are necessary. Therefore, the cost of chitin and chitosan preparations was far higher than those of their raw materials, marine chitin-containing byproducts. Chitin and chitosan have been widely used as the major carbon source of bacteria for producing chitinolytic enzymes. In 1997, the bifunctional chitinase/lysozymes from Pseudomonas aeruginosa K-187 using shrimp and crab shells as the sole carbon/nitrogen (C/N) source was first reported. Thereafter, the use of squid pens as the only C/N source for producing enzymes and bioactive materials had also been studied. The use of shellfish chitin waste as the sole C/N source not only solves environmental problems, it decreases the production costs for microbial conversion. This review summarizes our recent research of microbial reclamation of these marine byproducts for producing enzymes and bioactive materials; the characterization and applications of these products were also studied.