Biotechnology instead of chemistry

Article of 25 September 2020 

Biotechnological production

No matter whether medicines, food or everyday products such as detergents and cleaning agents – biotechnology has become an integral part of industrial production processes. This is due to the more environmentally friendly production process. This is because microorganisms such as bacteria, algae or fungi manage complex substance transformations with high yields at room temperature and under normal pressure. In contrast, chemical processes often require high temperatures and pressures. Furthermore, waste products are produced that pollute the environment.

In the case of surfactants, for example, biotechnological production takes place as follows: in a container, microorganisms are fed with extracts from sugar production residues, but also with extracts from wood, insects, etc. Air is also added. The microorganisms then produce the desired surfactants. These are important active ingredients for cleaning, as they dissolve and bind fat.

In order to obtain the optimum amount of surfactants, it is important to grow sufficient microorganisms, also known as biomass. For this purpose, air and a certain type and quantity of sugar must be added and the temperature and pH value must be readjusted. How the framework conditions are adapted will be decided depending on the growth rate of the biomass: if, for example, there is too little biomass, it may make sense to add more nutrients than originally planned so that the biomass can grow faster.

Roughly simplified, the feeding of sugars and oxygen leads to biomass growth. The metabolic product of biomass is CO2.
Roughly simplified, the feeding of sugars and oxygen leads to biomass growth. The metabolic product of biomass is CO2.

Determine biomass relatively precisely and cost-effectively with soft sensors

Measuring biomass is one of many challenges. In price-sensitive, industrial production processes, it is often too imprecise or too expensive for the biotechnological production of mass products such as surfactants to be competitive. For this reason, chemical production is still the most common option here.

In order to reduce costs, Festo is investigating the relatively precise and cost-effective soft sensor technology method to determine the biomass – that is, the quantity of bacteria. Existing measurement data and other known information are used to calculate the unknown quantity – here, the sum of the microorganisms which equates to biomass.

The calculation includes the supply of nutrients and air as well as the measured values of temperature, dissolved oxygen, pressure, reactor filling level, pH value and the amount of CO2 exhaled by the bacteria. The fact that the data is continuously recorded online means that the process can be optimised and the product yield increased. Thanks to this cost-effective calculation method, biotechnological processes are increasingly becoming an alternative to chemistry.

The calculation of the biomass includes the supply of nutrients and air, the reactor filling level and the amount of CO2 exhaled by the bacteria.
The calculation of the biomass includes the supply of nutrients and air, the reactor filling level and the amount of CO2 exhaled by the bacteria.

Biotechnological alternatives to chemical processes also exist for other products. Here the processes are very similar to those of the surfactants. For example, moulds are used in the food industry to produce citric acid. Genetically modified bacteria can also produce medical agents such as human insulin.