PRODUCTION OF CELLULASE ENZYME FROM ASPERGILLUS SPECIES USING CYPERUS ESCULENTUS

CHAPTER ONE

INTRODUCTION

1. Introduction:

Biotechnology offers an increasing potential for the production of goods to meet various human  needs. In enzyme technology– a subfield of biotechnology- new processes have been and are being developed to manufacture both bulk and high value added products utilizing enzymes as biocatalysts in other to meet needs such as food (bread, cheese,beer, vinegar) fine chemicals (e.g amino acids, vitamins) and pharmaceuticals. Enzymes are also used to provide services, as in washing and environmental processes or for analytical and diagnostic purposes.

The driving force in the development of enzyme technology, both in academia and in industry, has been and will continue to be development of new and better products, processes and services to meet these needs or the improvement of processes to produce existing products from new raw materials such as biomass. The goal of these approaches is to design innovative products and processes that not only are competitive but also meet criteria of sustainability. The concept of sustainability was introduced by the World Commission on Environment and Development, WCED, 1987 with the aim to promote a necessary “… development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” This definition is now part of the Cartagena protocol on biosafety to the convention on biological Diversity, an international treaty governing the movements of living modified organisms (LMOs) resulting from modern biotechnology from one country to another. It was adopted on January 29, 2000 as a supplementary agreement to the conventionon Biodiversity and entered into forceon September 11, 2003. It has now been ratified by 160 states.

Enzymes, the biological catalysts are considered as nature’s gifts. They function as protein robots inside the cells and speed up the biological processes without undergoing any change (Lanka and Latha, 2015). ). Enzymes are widely applied in the field of scientific research, cosmetic production, medical diagnostics, chemical analyses, therapeutic applications and industrial catalysis (Sharma et al 2001b).

Cellulase enzyme has been used for the bioconversion of lignocellulosic to these useful products. The production of bio-based products and bioenergy from less costly renewable lignocellulosic materials would bring benefits to the local economy, environment, and national energy security (Zhang, 2008). Many fungi produce enzymes that enable them to break down polysaccharides and proteins into sugars and amino acids that can be assimilated easily. These enzymes are important industry.  Approximately 90% of all industrial enzymes are produced in submerged fermentation (SmF), frequently using specifically optimized, and genetically manipulated microorganisms. In this respect SmF processing offers an insurmountable advantage over Solid state fermentation (SSF). Interestingly, fungi, yeasts and bacteria that were tested in SSF in recent decades exhibited different metabolic strategies under conditions of solid state and submerged fermentation.

Cellulases are the enzymes that hydrolyze β -1, 4 linkages in cellulose chains. They are produced by fungi, bacteria, protozoans, plants, and animals. The catalytic modules of cellulases have been classified into numerous families based on their amino acid sequences and crystal structures (Henrissat, 1989). In nature, complete cellulose hydrolysis is mediated by a combination of three main types of cellulases: (1) endoglucanases (EC 3.2.1.4), (2) exoglucanases, including cellobiohydrolases (CBHs) (EC 3.2.1.91), and (3) β -glucosidase (BG) (EC 3.2.1.21). To hydrolyze and metabolize insoluble cellulose, the microorganisms must secrete the cellulases (possibly except BG) that are either free or cell-surface-bound.

Notwithstanding the fact that  only 2% of the world’s microorganisms have been recognized as enzyme sources ( Jayesreeet al., 2014), microbial enzymes have a number of advantages over enzymes of plant and animal origin including the fact that: they have a greater potential for catalytic diversity, higher productivity within a short period of time, ease of genetic manipulation/optimization, independent of seasonal fluctuations, rapid growth  of the producing microorganisms on inexpensive media, greater functional stability (Wiseman, 1995)

1.2 Aim and Research objectives

The aim of this research is to produce cellulase enzyme from Aspergillus species using Cyperus esculentus. The objectives are to determine the,

• effect of temperature,
• effect of pH,
•  metal ions,
• And buffer solutions during the assay of cellulose.