Lignocellulosic materials are among the most promising alternative energy resources that can be utilized to produce cellulosic ethanol. However, the physical and chemical structure of lignocellulosic materials forms strong native recalcitrance and results in relatively low yield of ethanol from raw lignocellulosic materials. An appropriate pretreatment method is required to overcome this recalcitrance. For decades various pretreatment processes have been developed to improve the digestibility of lignocellulosic biomass. Each pretreatment process has a different specificity on altering the physical and chemical structure of lignocellulosic materials. In this paper, the chemical structure of lignocellulosic biomass and factors likely affect the digestibility of lignocellulosic materials are discussed, and then an overview about the most important pretreatment processes available are provided. In particular, the combined pretreatment strategies are reviewed for improving the enzymatic hydrolysis of lignocellulose and realizing the comprehensive utilization of lignocellulosic materials.

The role of pretreatment in improving the enzymatic hydrolysis

Himalayan perceptions: environmental change and the Well-being of Mountain peoples

Pectinase, a group of pectin degrading enzymes, is one of the most influential industrial enzymes, helpful in producing a wide variety of products with good qualities. These enzymes are biocatalysts and are highly specific, non-toxic, sustainable, and eco-friendly. Consequently, both pectin and pectinase are crucially essential biomolecules with extensive applicatory perception in the biotechnological sector. The market demand and application of pectinases in new sectors are continuously increasing. However, due to the high cost of the substrate used for the growth of microbes, the production of pectinase using microorganisms is limited. Therefore, low-cost or no-cost substrates, such as various agricultural biomasses, are emphasized in producing pectinases. The importance and implications of pectinases are rising in diverse areas, including bioethanol production, extraction of DNA, and protoplast isolation from a plant. Therefore, this review briefly describes the structure of pectin, types and source of pectinases, substrates and strategies used for pectinases production, and emphasizes diverse potential applications of pectinases. The review also has included a list of pectinases producing microbes and alternative substrates for commercial production of pectinase applicable in pectinase-based industrial technology. Key points
 • Pectinase applications are continuously expanding. • Organic wastes can be used as low-cost sources of pectin. • Utilization of wastes helps to reduce pollution.

New insights in pectinase production development and industrial applications.

Three new species of the cyprinid genus Schizothorax from Lake Rara, northwestern Nepal.

Formulation of the agro-waste mixture for multi-enzyme (pectinase, xylanase, and cellulase) production by mixture design method exploiting Streptomyces sp.

Pectinases are a group of enzymes with broad application, including in plant fiber processing, pectic wastewater treatment, paper pulping, fruit juice extraction, and clarification. With an increasing industrial demand for these enzymes, it is useful to isolate organisms that produce large amounts of pectinase and possess wide ranges of stability factors like temperature and pH. In this study, 17 out of 29 bacteria (58.62%) from forest soil samples were pectinolytic. However, only four bacteria (S-5, S-10, S-14, and S-17) showed high pectin hydrolysis zones (ranging from 0.2 cm to 1.7 cm). These four bacteria were identified based on colony morphology, microscopic characterization, biochemical characteristics, and 16S rDNA sequencing. They were designated as Streptomyces sp. (S-5, S-14), Cellulomonas sp. (S-10), and Bacillus sp. (S-17). Interestingly, bacteria showed cellulase and xylanase activity in addition to pectinase. The quantitative assay for pectinase activity of the four isolates provided proof that they are pectinase producers and can be considered potential candidates for industrial uses. The crude enzyme extracts of these bacteria are applicable in oil and juice extraction from sesame seeds and apples, respectively.

Screening and Molecular Identification of Novel Pectinolytic Bacteria from Forest Soil

Nepal is known for its rich freshwater resources that support diverse flora and fauna. These freshwater ecosystems provide countless goods and services to human kind but are in tremendous pressure mainly due to human activities. As a result, there has been sharp decline of hydrological, economic and ecological functions, good and services from wetlands. In this review, we explored the geographical distribution patterns, biodiversity, existing threats, goods and ecological services provided by the wetland/fresh water ecosystem in Nepal. The review also discusses the conservation history of wetlands and identifies the gaps and suggests priority hotspots for the formulation of future conservation strategies for these ecosystems.

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Freshwater biodiversity in western Nepal: A review

The increase in human population with the increase in nutritional awareness for fruits and vegetables consumption is forcing toward higher production and supply of fruits and vegetables. However, some sorts of food processing steps are involved before human consumption which is essential for preserving the properties of those fruits and vegetables. During these processes and till reaching the consumers, many fruits and vegetables wastes are produced. Although the emphasis was given to produce less waste and reuse the products as much as possible, utilization of those wastes in bioprocessing and production of different value-added products were less emphasized. Thus, in this chapter, we describe the major value-added bioproducts produced from fruits and vegetables wastes such as bioactive compounds, phenolic compounds, enzymes, pigments, flavoring compounds and aroma, dietary fibers, organic acids, bioenergy, bioplastics, exopolysaccharides, single-cell protein, etc.

Bioconversion of Fruits and Vegetables Wastes into Value-Added Products

Chloroplast genome analysis of Chrysotila dentata.

Hydrogen is a promising alternative to fossil fuels because of its environment-friendly characteristics. It has been used widely in varied sectors such as chemical production, electronic devices, food industries, desulfurization of crude oil, and steel industries. Due to its increasing use and demand, it is essential to develop a cheaper and energy-efficient source of hydrogen production. This review synthesizes and discusses various aspects of hydrogen production methods and processes, the challenges, and economic perspective for sustainable production of biohydrogen. Compared to electrolysis, thermochemical and electrochemical processes, the biohydrogen production is environment friendly and energy efficient. Various factors such as feedstock, pH, temperature, partial pressure of hydrogen, and hydraulic retention time are responsible for the biological process and yield of biological hydrogen production. This review suggests that lignocellulosic biomass is commonly available, cheaper and eco-friendly source of hydrogen production.

Janak Raj Khatiwada

Papers

Screening and Molecular Identification of Novel Pectinolytic Bacteria from Forest Soil

Freshwater biodiversity in western Nepal: A review

Bioconversion of Fruits and Vegetables Wastes into Value-Added Products

Chloroplast genome analysis of Chrysotila dentata.

Bioconversion of Hemicelluloses into Hydrogen