Genetic engineering and engineering in general are two distinct fields that people tend to separate due to conflict of interest between experts. Genetic engineering is the manipulation of an organism genome using biotechnology while engineering is the creation and application of tools and machineries that helps or enhance ability of human to manage this world. Manipulating of the genetic code in terms of producing new materials or increase the production of certain valuable materials of interest is considered as engineering, as it fulfils the meaning of creation. Various coagulants have been employed to reduce water turbidity. Coagulants are divided into three types; as natural inorganics, natural organics and chemical coagulants. The subject of this review is based on M. oleifera protein (lectin) as natural coagulant. Several attempts to extract coagulant from seeds of M. oleifera are already reported. Researchers are also working on the production of alternatives to M. oleifera lectin via genetic engineering approach. The expression of M. oleifera lectin from E. coli has been reported to provide high and pure lectin with enhanced efficiency in the removal of water turbidity. Future interest in using higher eukaryote system especially P. pastoris and genetically modified lectin is expected to increase both production volume and improve coagulation properties. The release and consumption of this lectin raises a few questions about health and environmental safety. This review analyses positive and negative influence of the genetic engineering technique based on various studies done in relation to producing natural organic coagulants, such as lectin.