초록
<P>Citric acid (CA) is the most important organic acid used in the food and other industries. <I>Locusta migratoria</I> is an insect species, which has rich nutritional composition (especially protein) and cultivated in some countries. Therefore, the present study investigated the usability of hydrolysate extract of <I>L. migratoria</I> biomass as substrate for the production of CA from <I>Aspergillus niger</I> MT-4. The insect extract (IE) was found to be rich in ash (34.9 g/100 g), protein (35.6 g/100 g) and mineral contents. Yeast extract was found to be the most favorable substrate for biomass production, whereas the maximum production of CA (41.8 g/L) was achieved in the medium containing IE. Besides, uniform pellets with the smallest size (4 mm) were observed in IE medium. It was thought that rich magnesium (6.78 g/100 g) and manganese (1.14 g/100 g) contents of IE increased the production of CA, resulting in the formation of small uniform pellets. This is the first report on the effect of protein-rich insect biomasses on the production of CA. In this regard, <I>L. migratoria</I> biomass was tested for the first time as a CA-production substrate.</P>