Abstract: Brazil is the world’s largest producer of orange and passion fruit, which are destined mainly for industrialization, generating grand volumes of wastes. The solid portion of these residues is a rich source of pectin - composed mainly of galacturonic acid and neutral sugars, which through the hydrolysis process can be used in biological conversion processes, as the production of polyhydroxyalkanoates (PHAs). This way, we characterized these wastes, followed by the extraction and hydrolysis of pectin for employ as a substrate for the cell growth of Cupriavidus necator. The results confirmed the large portion of pectin (almost 40 g.100g-1) and soluble sugars, present in these wastes. The hydrolyzed extract showed as a good source of carbon for the cell growth of C. necator with YX/S 0.56 and 0.44, µMax 0.27 and 0.21 for orange and passion fruit wastes respectively, similar to other carbon sources. This way, the extraction and hydrolysis of orange and passion fruit wastes for the cellular growth of C. necator, can be a good alternative to converting of residues in high value added product.

Abstract: The present work investigated what the appropriate methods of hydrolysis of pectin for reducing compounds (RCs) production, employed as a substrate for cell growth of Cupriavidus necator. This microorganism has great importance industrial, because besides potential single cell protein (SCP), is the most studied microorganism for production of polyhydroxybutyrate (PHB), and both processes require high cell concentration with inexpensive substrates For this, it was compared to acid and enzymatic hydrolysis procedures, through rotational central composite experimental design, using pectin concentration (1.0%). It was analyzed as a variable response for both experimental design, the RCs’ production. The best conditions of each procedure were used in study kinetics of RCs’ production and as a substrate for cell growth of C. necator. The results indicated that the enzymatic hydrolysis method was the most efficient, with a 93.0% yield of RCs, while the yield for acid hydrolysis was 60.0%. The optimum conditions for enzymatic hydrolysis were an enzyme concentration of 10.01 UI/g (International Unit of enzyme per gram of pectin) and an agitation speed of 230.3 rpm. C. necator showed satisfactory growth in the media containing pectin hydrolysates, with specific growth rates (μMax) similar to those reported for other substrates.