Biomass and Exopolysaccharide Production by Morchella Esculenta in Submerged Culture Using the Extract From Waste Loquat (Eriobotrya Japonica L.) Kernels

Abstract

Detoxified loquat kernel extract (DLKE) and neutralized loquat kernel extract (LKE) prepared from waste loquat kernels were used as main carbon sources in the submerged and solid cultures of Morchella esculenta. LKE and DLKE were found to be good substrates as they resulted in mycelial biomass and exopolysaccharide (EPS) concentrations near to those obtained with malt extract (ME). In the production media prepared with ME, DLKE and LKE, the maximum biomass concentrations were 18.9, 16.7 and 14.6 g/L, and the maximum EPS concentrations were 5.3, 5.2 and 4.1 g/L, respectively. EPS produced by mushrooms has various biologic and pharmacologic activities, including antitumor, immunostimulating and hypoglycemic activities. On the other hand, mushroom mycelia produced by submerged fermentation have the potential to be used in the human diet. To the best of our knowledge, this is the first report on the usability of this waste material as a substrate in microbial culture media. PRACTICAL APPLICATIONS The hydrolyzate prepared from loquat kernel flour was used for the preparation of detoxified and neutralized extracts. Both extracts could be effectively used as a substrate in the submerged and solid cultures of Morchella esculenta; however, their usage in submerged culture will be more advantageous as submerged culture provides faster and more efficient production of mycelial biomass and exopolysaccharide (EPS) in mushrooms. The present study is very important for industrial, environmental and food microbiology as it proved that an agricultural origin‐waste material could be effectively utilized as a substrate for the production of mycelial biomass and EPS in submerged culture of an edible mushroom.

L‐lactic acid production by Rhizopus oryzae MBG‐10 using starch‐rich waste loquat kernels as substrate

“…4B). L-lactic acid and biomass concentration were stable in 60-72 h. But, a reduction in total biomass amount of the fungus was recorded after 72 h. In contrast to biomass, little increase in lactic acid was detected in 72-84 h. These results could be attributed to fungal cell lysis, which appears with the depletion of sugar content in the culture medium [13]. That is to say L-lactic acid inside mycelia was liberated into the medium when mycelia was exposed to fungal cell lysis, and therefore little increase in L-lactic acid concentration was observed in 72-84 h. A similar effect of prolonged incubation time on L-lactic acid and biomass concentrations was also observed in LKF medium as described in Fig.…”

“…Selections of a low-cost substrate and a microbial strain with high activity are accepted as very important aspects in microbial fermentations [11][12][13]30]. In this study, these aspects were optimized for maximum lactic acid production.…”

“…The starch accounts for 25.6% of total carbohydrate and 36% of whole kernel, on dry weight basis [10]. Recently, we informed that loquat seed kernels could be used as a novel substrate for microbial production of carotenoids [11] and exopolysaccharides [12,13]. In another study, loquat kernel could be effectively used as a novel amylase production substrate thanks to its rich starch content [10].…”

Evaluation of Waste Loquat Kernels as Substrate for Lipid Production by Rhodotorula glutinis SO28

“…Loquat kernel extract (LKE) was re-prepared by applying acid hydrolysis and neutralization procedures according to the previous method [19]. HCl and NaOH were used for the hydrolysis and neutralization steps, respectively.…”

“…Loquat kernels are reported to have high carbohydrate (71.2 %) content. The kernels are also rich in minerals, specially potassium, calcium and magnesium [19]. Due to rich nutritional composition, powdered loquat kernels or hydrolysate (extract) prepared from these kernels are used as substrate for exopolysaccharide, enzyme, organic acid and carotenoid production [20].…”