Biotransformation of lignocellulosic biomass into industrially relevant products with the aid of fungi-derived lignocellulolytic enzymes.

Lignocellulosic material has drawn significant attention among the scientific community due to its year-round availability as a renewable resource for industrial consumption. Being an economic substrate alternative, various industries are reevaluating processes to incorporate derived compounds from these materials. Varieties of fungi and bacteria have the ability to depolymerize lignocellulosic biomass by synthesizing degrading enzymes. Owing to catalytic activity stability and high yields of conversion, lignocellulolytic enzymes derived from fungi currently have a high spectrum of industrial applications. Moreover, these materials are cost effective, eco-friendly and nontoxic while having a low energy input. Techno-economic analysis for current enzyme production technologies indicates that synthetic production is not commercially viable. Instead, the economic projection of the use of naturally-produced ligninolytic enzymes is promising. This approach may improve the economic feasibility of the process by lowering substrate expenses and increasing lignocellulosic by-product's added value. The present review will discuss the classification and enzymatic degradation pathways of lignocellulolytic biomass as well as the potential and current industrial applications of the involved fungal enzymes.

Dissimilatory reduction of Fe(III) by a novel Serratia marcescens strain with special insight into the influence of prodigiosin.

A novel pigmented bacterium, initially identified as 11E, was isolated from a site historically known to have various iron-related ores. Phylogenetic analysis of this bacterial strain showed that it belongs to Serratia marcescens. This pigmented S. marcescens 11E cultured individually with glucose, acetate, and glycerol as electron donors along with the soluble electron acceptor iron (Fe) (III) citrate offered a large reduction extent (45.3 %, 31.4 %, and 13.5 %, respectively). On the other hand, when iron oxide (Fe2O3) is used as electron acceptor, the pigmented strain produced a null reduction extent. Surprisingly, the absence of prodigiosin on the bacterial surface (non-pigmented strain) resulted in a large reduction extent of the non-soluble iron form (20-49%). All these extents were comparable and, in some cases, superior to those presented in the literature. Additionally, in the present study, it was found that anthraquinone sulfonate (AQS) stimulated Fe(III) reduction of soluble and non-soluble Fe species only with pigmented S. marcescens. In contrast, in the culture media with the non-pigmented strain, the presence of AQS did not stimulate the Fe(III) reduction. These results suggest that the pigmented phenotype of S. marcescens 11E may perform non-soluble Fe(III) reduction by electron shuttling. In contrast, for the non-pigmented phenotype of this bacterium, non-soluble Fe(III) reduction seems to proceed by direct contact. Our study demonstrates that this bacterium may be used in bioreduction process of heavy metals or as a biocatalyst in bioelectrochemical devices.

Algal-based removal strategies for hazardous contaminants from the environment - A review.

Owing to the controlled or uncontrolled industrial wastewater disposal, pharmaceutical-based hazardous emerging contaminants (ECs) can be found in the environment all over the world. With ever-increasing socioeconomic aspects and environmental awareness, people are now more concerns about the widespread occurrences of hazardous and persistent contaminants, around the globe. In this context, several studies have already shown that various types of emerging and/or re-emerging contaminants, regardless the source, type and concentration, are of supreme threat to the living system of flora and fauna. Recently, algae-based bioreactors have gained special research interest as a promising way to remove pharmaceuticals-based ECs from the wastewater either partially or completely. This paper covers the progress on the removal of selected pharmaceuticals using bioreactors. In laboratory scale studies, high removal percentages have been reached for most selected pharmaceuticals, but data on full-scale bioreactors is limited. In this paper, two types of bioreactors are discussed, i.e., (1) open pond and (2) bubble column photobioreactor, which are considered sustainable and an effective alternative to remove ECs. In these bioreactors, high removal percentages (>90%) have been found for metoprolol, triclosan, and salicylic acid, moderate (50-90%) for carbamazepine and tramadol and very low (<10%) for trimethoprim and ciprofloxacin by inoculating different microalgae. This technique may open new opportunities for the treatment of wastewater and reduce the environmental pollution that can have adverse effects on the ecosystem and human health. In summary, the present review focuses on the microalgae for wastewater remediation. An effort has also been made to describe the generalities of the photobioreactor.

Emergent contaminants: Endocrine disruptors and their laccase-assisted degradation - A review.

Herein, an effort has been made to highlight the trends of the state-of-the-art of laccase-assisted degradation of emerging contaminants at large and endocrine disruptors in particular. Since first described in the 19th century, laccase has received particular interest for inter- and multidisciplinary investigations due to its uniqueness and remarkable biotechnological applicability. There has always been a paramount concern over the widespread occurrences of various pollutant types, around the globe. Therefore, pollution free processes are gaining ground all over the world. With ever increasing scientific knowledge, socioeconomic awareness, human health-related issues and ecological apprehensions, people are more concerned about the widespread environmental pollutants. In this context, the occurrences of newly identified pollutants so-called "emerging contaminants - ECs" in our main water bodies is of continued and burning concern worldwide. Undoubtedly, various efforts have already been made to tackle this challenging ECs concern though using different approaches including physical and chemical, however, each has considerable limitations. In this review, we present information on how laccase-assisted approach can change this limited tendency of physical and chemical based approaches. A special focus has been given to the laccase-assisted systems including pristine laccase, laccase-mediator catalyzed system and immobilized-laccase catalyzed system that promotes the endocrine disruptors removal. Towards the end, a list of outstanding questions and research gaps are given that can pave the way for future studies.