FILAMENTOUS FUNGI OF WASTE BIOMASS OF HIGHER WATER PLANTS - Biochemistry and Biotechnology: Research and Development - page 160

1. Association of microorganisms and HWP. HWP possess extremely developed root

system, which hold certain portion of biogens (nitrogen, phosphorus) and pollutants
incoming to ecosystem from sewages, and serves as natural immobilizer for
microorganisms that participate in transformation of pollutants.

2. Benthos, holding and absorbing part of biogens and pollutants migrating on border of

division water/bottom deposits.

3. Microorganisms.

Thus, the more pollutants were in sewages the more pollutants are absorbed by HWP
biomass, which will create extreme conditions for development of microorganisms.
It is necessary to note that HWP are characterized by valuable biofuel properties and high
productivity. Water lettuce Pistia stratiotes cultivated on sewages gives more than 1 kg of
biomass growth from 1 m 2 of water surface daily, which makes 90-135 tons of dry biomass
from 1 hectare of water surface per season. HWP applied for sewage cleansing contain
protein, cellulose, oils, water soluble polysaccharides. That is why waster biomass of HWP
represents certain interest for its transformation into biofuel (biogas, bioethanol). Isolation of
microorganisms from natural biocenosis, which are capable to degrade cellulose, and
determination of optimal cultivation conditions for their utilization of substrates containing
certain pollutants is perspective approach for biofuel production.
We conducted search and isolation of micromycetes from waste HWP biomass that
possess cellulase activity and natural resistance to certain pollutants.
For that purpose we used biomass of HWP cultivated on sewages of oil-and-gas industry.
Czapek-Dox and modified Czapek-Dox media were used for isolation of micromycetes by
method of subsequent dilutions [2]. Reduced sugars wre determined according to Somogyi-
Nelson [3]. Incubation of micromycetes was conducted 6-7 days. Taxonomy of micromycetes
was determined according corresponding manuals [4, 5].
As result of conducted study it was established that in process of sewages cleansing with
application of association of HWP and microorganisms not only total quantity of
microorganisms isolated from biomass raised but their taxonomic structure changed as well.
Phenomenon of “domination concentration” is well known for macroorganisms in stress
conditions. Similar pattern in reaction of micromycetes was observed at analysis of rotten
rice, where Penicillium , Aspergillus and Stachybotrys were prevailing species among isolated
fungal cultures [6]. We observed same type of reactions on pollution of water reservoirs at
analysis of waste HWP biomass, which in this case serves as immobilizer not only for
microorganisms but for a number of pollutants as well.
At stress conditions of pollution certain groups of micromycetes prevailed with increased
concentration of pollutants in sewage. Filamentous fungi isolated from waste biomass
belonged mainly to genera Aspergillus and Penicillium. At the same time density of
Aspergillus species raised by 2-3 times compared to number of Aspergillus species isolated
from biomass cultivated in fresh water (figure 1), whereas prevailing fungi on waste biomass
from fresh water belonged to Fusarium genus.
Different cultures of filamentous fungi were isolated from waste HWP biomass, which
were studied for ability to degrade cellulose. According to cellulase active following cultures
were selected: Aspergillus niger, A. terreus , A. flavus, Penicicillium griseo-roseum. These
cultures expressed good growth on Mandels medium with filter paper and on modified
Czapek-Dox medium with addition of cellulose substrate.