A critical factor in obtaining a suitable inoculum is the choice of the culture medium. This media is designed for rapid microbial growth, and little or no product accumulation normally occurs. Requirements mainly depend on the type of microorganism employed in the fermentation process. However, the essentials for microorganisms do remain the same, that are, the source of energy, water, the carbon source, nitrogen source, vitamins and minerals. The culture medium should:
- allow high yield of the desired product at a rapid rate
- cause suppression of undesired products
- be easily sterilized
- yield consistent products with minimum environmental hazards during the entire fermentation process
Important components of the medium are carbon sources, nitrogen sources, minerals, growth factors, chelating agents, buffers, antifoaming agents, air, steam, and fermentation vessels. Defined or formulated media have very little batch variation but are expensive. The media should support the metabolic process of the organism to facilitate the biosynthesis of the desired products.
It is crucial to note that effective inoculum development is equally important regardless of the scale of fermentation.
Safety guidelines while using recombinant DNA microorganisms: There is no doubt that genetically engineered or recombinant microorganisms have improved the quality of production for small scale as well as large industries and has wide scope in terms of research. But there are certain safety measures to be taken and certain guidelines to be followed when handling such microorganisms. There are certain official governmental and institutional bodies that lay out such guidelines and regulations to be followed. These guidelines must be followed during research in laboratory (i.e.) development of the inoculum and during the actual production process and extra care must be taken while releasing these microorganisms, as they may be potentially harmful. The Department of Biotechnology, working under government of India, has been updating its guidelines and regulations since they first came out in 1990 and now the present-day guidelines titled “Regulations and Guidelines for Recombinant DNA research and Biocontainment, 2017” is made available and can be accessed through their official website.
Containment: Containment includes safe methods (combination of facilities, practices and procedures) for managing risk-inherent genetically engineered organisms in the laboratory environment where they are handled or maintained. Selecting an appropriate containment strategy will provide safety to laboratory workers, outside people, and the environment from hazardous microorganisms as it will reduce the exposure and prevent their escape and establishment in the natural environment. Concerns about microorganisms derived by rDNA technology is that the genetic modification might affect their host range and convert them into pathogens and/or alter the balance between them and ecologically interrelated populations in the ecosystem.
Biological safety levels: All the facilities handling microorganisms containing recombinant DNA molecules must have risk assessment programs and depending on the risk possessed by the samples, the microorganisms can be divided into four risk groups i.e. RG1 to RG4, and then be operated under suitable biosafety level categories.
Laboratory monitoring: Laboratory monitoring is a systematic, regular and preventive activity designed for corrective actions, if needed. A manual of laboratory monitoring should be prepared and kept in the facility information and ready reference to workers.
Decontamination and disposal: Decontamination and disposal in laboratories are closely interrelated acts since disinfection or sterilization constitute the first phase of disposal. All materials to be disposed or waste must be managed appropriately.