Band 6, Heft 5

Colored pigments are inorganic or organic colorants, which are insoluble in the application media, where they are incorporated for the purpose of coloration. Their optical action is based on the selective light absorption together with light scattering. Colored pigments do not include pigments that are colored but which are not used because of their colored character but because of properties such as corrosion protection and magnetism. White pigments, black pigments, grey pigments, effect pigments, and luminescent pigments also do not belong to the colored pigments.

Bacteria and fungi have a high potential to produce compounds that display large structural change and diversity, thus displaying an extensive range of biological activities. Secondary metabolism or specialized metabolism is a term for pathways and small molecule products of metabolism that are not mandatory for the subsistence of the organism but improve and control their phenotype. Their interesting biological activities have occasioned their application in the fields of agriculture, food, and pharmaceuticals. Metabolic engineering is a powerful approach to improve access to these treasured molecules or to rationally engineer new ones. A thorough overview of engineering methods in secondary metabolism is presented, both in heterologous and epigenetic modification. Engineering methods to modify the structure of some secondary metabolite classes in their host are also intensively assessed.

Colors are only created in the human brain. During this process, light rays from the environment reach the retina of the eye. There they trigger an optical stimulus, which is transmitted to the brain. And the brain translates this stimulus into colors. The perception of color is influenced by multiple factors, which is why it is highly subjective. Originally, the light rays come from the sun. They are described by the color spectrum, which comprises rays visible to us from 400 to 700 nm. These light rays can be influenced by different pigments that manipulate the light rays. This manipulation can happen by absorption, reflection and refraction and interference.

In the today’s context of COVID-19, when a strong need of disposable items without compromising the environmental attributes is being felt, “Paper” is becoming a very mesmerizing and quintessential object. We find paper in our lives so omnipresent and enduring that we take it granted without understanding its complex nature, manufacturing/development process and the significant role, it has actually played in the history of civilization. It is so important that the Per Capita Consumption of paper for a country reflects the development status of its society. Therefore, this article attempts to introduce paper with its historical development, manufacturing process, environmental concerns, ways to address the environmental concerns, global and national status of pulp and paper industry along with the challenges ahead with a coverage of the potential role it is bound to play in future through an overall transformation of the industry itself.

Dissolving pulps are high-grade cellulose pulps that have minimum amount of non-cellulosic impurities. Dissolving pulps are the basic source for the manufacturing of several cellulosic products such as viscose, lyocell, cellulose acetates, cellulose nitrates, carboxymethyl-cellulose, etc. Dissolving pulps are mainly manufactured by pre-hydrolysis kraft and acid sulphite pulping. A high reactivity of dissolving pulps is desirable for its eco-friendly utilization for several purposes. Several approaches including mechanical, chemical, ultrasonic, and enzymatic treatments have been employed for the improvement of pulp reactivity. This review mainly focussed on pulp reactivity improvement through enzymatic approaches. Cellulases and xylanase have been proved effective for the improvement of pulp reactivity of dissolving pulp from different sources. The different combinations of cellulase, xylanase, and mechanical refining have been tested and found more effective rather than the single one.

Iron blue pigments are representatives of the inorganic blue pigments. They are characterized by a sufficient hue, high tinting strength, and suitable rheological properties. Iron blue pigments are subdivided into “soluble iron blue” and “insoluble iron blue”. Both pigments are synthesized using precipitation techniques. Iron blue pigments are mainly used in printing applications. Special uses of the pigments are agriculture and medicine.