TY - JOUR

T1 - Algae Cultivation as Measure for the Sanitation of Organic Waste—A Case Study Based on the Alga Galdieria sulphuraria Grown on Food Waste Hydrolysate in a Continuous Flow Culture

AU - Pleissner, Daniel

AU - Händel, Nicole

N1 - Funding Information: This research is funded by the German Federal Ministry of Education and Research (BMBF), in the frame of FACCE-SURPLUS/FACCE-JPI project UpWaste, grant number 031B0934B and by the PRIMA programme (project “Cipromed”) supported and funded under 2020, the framework European Union’s programme for research and innovation. Publisher Copyright: © 2023 by the authors.

PY - 2023/10/1

Y1 - 2023/10/1

N2 - Due to its growth under harsh acidic conditions, the microalga Galdieria sulphuraria may offer the opportunity to combine sanitation and the utilization of organic waste streams. To further deepen the knowledge of alternative waste treatment strategies that allow for holistic utilization, the control and removal of microbial contaminants via non-sterile heterotrophic G. sulphuraria on food waste hydrolysate were investigated in a continuous flow bioreactor culture. Furthermore, a substrate reservoir and harvested biomass were stored under non-sterile conditions over a period of 12 days. Despite the non-sterile conditions, the microbial load of the biomass could be kept under control. Neither the pathogen Salmonella sp. nor the coliform bacteria Escherichia coli could be found. Only nine counts per g of biomass were found for species belonging to Enterococcus spp., Enterobacteriacae, and moulds. Aerobic spore formers were counted with 2700 counts per g of biomass. Most of the aerobic mesophilic counts were formed by yeasts (1.5 × 106 vs. 1.3 × 106 counts per g biomass). The results revealed that, when using acidic growth conditions, contamination will not take over the culture; thus, the sterilization of waste materials can be skipped. It is assumed that such an approach can result in efficient processes for future waste-based bioeconomy strategies.

AB - Due to its growth under harsh acidic conditions, the microalga Galdieria sulphuraria may offer the opportunity to combine sanitation and the utilization of organic waste streams. To further deepen the knowledge of alternative waste treatment strategies that allow for holistic utilization, the control and removal of microbial contaminants via non-sterile heterotrophic G. sulphuraria on food waste hydrolysate were investigated in a continuous flow bioreactor culture. Furthermore, a substrate reservoir and harvested biomass were stored under non-sterile conditions over a period of 12 days. Despite the non-sterile conditions, the microbial load of the biomass could be kept under control. Neither the pathogen Salmonella sp. nor the coliform bacteria Escherichia coli could be found. Only nine counts per g of biomass were found for species belonging to Enterococcus spp., Enterobacteriacae, and moulds. Aerobic spore formers were counted with 2700 counts per g of biomass. Most of the aerobic mesophilic counts were formed by yeasts (1.5 × 106 vs. 1.3 × 106 counts per g biomass). The results revealed that, when using acidic growth conditions, contamination will not take over the culture; thus, the sterilization of waste materials can be skipped. It is assumed that such an approach can result in efficient processes for future waste-based bioeconomy strategies.

KW - bioeconomy

KW - bioprocess

KW - sanitation

KW - waste management

KW - waste streams

KW - Biology

UR - http://www.scopus.com/inward/record.url?scp=85174203367&partnerID=8YFLogxK

U2 - 10.3390/su151914313

DO - 10.3390/su151914313

M3 - Journal articles

AN - SCOPUS:85174203367

VL - 15

JO - Sustainability

JF - Sustainability

SN - 2071-1050

IS - 19

M1 - 14313

ER -