Byline: Mona. El-refai, Om Kalthoum. Khattab, Siham. Ismail, Amal. Hashem, Amany. Abo-Elnasr, Shaimaa. Nour
Objectives The aim of this research is to produce [sz]-mannanases from a new microbial source using wastes in their nutrition medium. The enzyme produced can be used for the production of galactomanno-oligosaccharides, which are very useful in the health and medical fields. Materials and methods Seven fungal strains and five bacterial strains were tested for the production of [sz]-mannanases. Enzyme activity, protein content, and biomass production were determined in all the cultures produced using standard methods. Optimization studies to maximize enzyme production from the most potent microorganisms, including culture conditions and medium compositions, were also carried out. Preliminary studies for the production of galactomanno-oligosaccharides from locust bean gum using partially purified enzymes were also carried out and followed by thin-layer chromatography techniques and Somogyi methods. Results and conclusion The highest mannanase activities were produced by Penicillium humicola (8.8 U/ml) and Penicillium spp. v (7.75 U/ml) in shaking cultures after 10 days using gum locust bean as a carbon source. Among 13 carbon sources examined, coffee residue and ceratonia seeds were the best carbon sources (10.3 and 8.9 U/ml, respectively) for P. humicola, whereas the best nitrogen source was a mixture of peptone, urea, and ammonium sulfate for the same microorganism. The optimum temperature and pH for enzyme reaction was 55 and 5.5[degrees]C, respectively. The enzyme was thermostable and retained 80% of its activity after 1 h at 50[degrees]C. The highest reducing sugar of 8900 [micro]g/ml was obtained from locust bean gum hydrolytes after 28 h.
Lignocellulose is a major component of plant cell walls and is mainly composed of lignin, cellulose, and hemicellulose. Mannans and heteromannans are a part of the hemicellulose fraction in plant cell walls. The structure of hemicellulose is a key component of many types of sugar such as xylans, mannans, heteromannans, galactans, and arabinans . Mannans and heteromannans are distributed widely in hardwoods and softwoods, seeds of leguminous plants, and bean . They can be divided into four types: unsubstituted (1, 4)-linked [sz]-d mannans, galactomannans, glucomannans, and galactoglucomannans . Mannans, whose main component is d-mannose, are important for several industries, including food, feed, and feed stocks. They can be broken down into simple sugars or oligosaccharides by a synergistic action of endomannanases (EC number 184.108.40.206, mannan endo-1, 4-[sz]-mannosidase) and exo-acting [sz]-mannosidase (EC number 220.127.116.11). The production of [sz]-mannanase by microorganisms is more promising because of its low cost, high production rate, and easily controllable condition .
Various microorganisms can produce mannanases such as Aspergillus awamori , Aspergillus oryzae , Penicillium oxalicum , Trichoderma harzianum , Rhodothermus marinus , Bacillus subtilis , and Streptomyces ipomoea .
Many mannan-based carbon sources including locust bean gum, guar gum, and copra meal have been used to cultivate filamentous fungi ,,. Moreover, various inducers were used to improve mannanase production. Chaiongkarn et al.  isolated microorganisms from soil using copra meal as a carbon source for their growth.
Therefore, this study aimed to search for cheaper...