Polyhydroxyalkanoates (PHAs) are high-value biodegradable polyesters with thermoplastic properties used in the manufacturing of different products such as packaging films. PHAs have gained much attention from researchers and industry because of their biobased nature and appropriate features, similar to conventional synthetic plastics. This review aims to discuss some of the recent solutions to challenges associated with PHA production. The implementation of a cost-effective process is presented by following different strategies, such as the use of inexpensive carbon sources, the selection of high-producing microorganisms, and the functionalization of the final materials to make them suitable for food packaging applications, among others. Research efforts are needed to improve the economic viability of PHA production at a large scale. Haloferax mediterranei is a promising producer of PHAs due to its ability to grow in non-sterile conditions and the possibility of using seawater to prepare the growth medium. Additionally, downstream processing for PHA extraction can be simplified by treating the H. mediterranei cells with pure water. Further research should focus on the optimization of the recycling conditions for the effluents and on the economic viability of the side streams reutilization and desalinization as an integrated part of PHA biotechnological production.

In this article we propose a model of innovation competence of people, based on the existing literature to integrate and complement the existing models. The main contribution of this work consists in demonstrating the differences and similarities of current models and in providing a conceptual definition for each model element. In this way, both researchers and people in charge of Human Resources in companies can obtain a framework to design measuring instruments to assess the innovation competence, which can fulfil the twofold demand requirement of validity and reliability.

The concept of function is a threshold concept in mathematics since it is essential for a deep understanding of the subject and is often problematic for students. Despite the importance of this concept, numerous studies have found that students have several difficulties and misconceptions about it. This work aims to assess, classify and synthesize the existing information about the learning difficulties and misconceptions related to the concept of function. In this sense, the main achievement of the work is the synthesis and classification by topics of the information gathered from the literature.